connections: introduce http/3 happy eyeballs

New cfilter HTTP-CONNECT for h3/h2/http1.1 eyeballing.
- filter is installed when `--http3` in the tool is used (or
  the equivalent CURLOPT_ done in the library)
- starts a QUIC/HTTP/3 connect right away. Should that not
  succeed after 100ms (subject to change), a parallel attempt
  is started for HTTP/2 and HTTP/1.1 via TCP
- both attempts are subject to IPv6/IPv4 eyeballing, same
  as happens for other connections
- tie timeout to the ip-version HAPPY_EYEBALLS_TIMEOUT
- use a `soft` timeout at half the value. When the soft timeout
  expires, the HTTPS-CONNECT filter checks if the QUIC filter
  has received any data from the server. If not, it will start
  the HTTP/2 attempt.

HTTP/3(ngtcp2) improvements.
- setting call_data in all cfilter calls similar to http/2 and vtls filters
  for use in callback where no stream data is available.
- returning CURLE_PARTIAL_FILE for prematurely terminated transfers
- enabling pytest test_05 for h3
- shifting functionality to "connect" UDP sockets from ngtcp2
  implementation into the udp socket cfilter. Because unconnected
  UDP sockets are weird. For example they error when adding to a
  pollset.

HTTP/3(quiche) improvements.
- fixed upload bug in quiche implementation, now passes 251 and pytest
- error codes on stream RESET
- improved debug logs
- handling of DRAIN during connect
- limiting pending event queue

HTTP/2 cfilter improvements.
- use LOG_CF macros for dynamic logging in debug build
- fix CURLcode on RST streams to be CURLE_PARTIAL_FILE
- enable pytest test_05 for h2
- fix upload pytests and improve parallel transfer performance.

GOAWAY handling for ngtcp2/quiche
- during connect, when the remote server refuses to accept new connections
  and closes immediately (so the local conn goes into DRAIN phase), the
  connection is torn down and a another attempt is made after a short grace
  period.
  This is the behaviour observed with nghttpx when we tell it to  shut
  down gracefully. Tested in pytest test_03_02.

TLS improvements
- ALPN selection for SSL/SSL-PROXY filters in one vtls set of functions, replaces
  copy of logic in all tls backends.
- standardized the infof logging of offered ALPNs
- ALPN negotiated: have common function for all backends that sets alpn proprty
  and connection related things based on the negotiated protocol (or lack thereof).

- new tests/tests-httpd/scorecard.py for testing h3/h2 protocol implementation.
  Invoke:
    python3 tests/tests-httpd/scorecard.py --help
  for usage.

Improvements on gathering connect statistics and socket access.
- new CF_CTRL_CONN_REPORT_STATS cfilter control for having cfilters
  report connection statistics. This is triggered when the connection
  has completely connected.
- new void Curl_pgrsTimeWas(..) method to report a timer update with
  a timestamp of when it happend. This allows for updating timers
  "later", e.g. a connect statistic after full connectivity has been
  reached.
- in case of HTTP eyeballing, the previous changes will update
  statistics only from the filter chain that "won" the eyeballing.
- new cfilter query CF_QUERY_SOCKET for retrieving the socket used
  by a filter chain.
  Added methods Curl_conn_cf_get_socket() and Curl_conn_get_socket()
  for convenient use of this query.
- Change VTLS backend to query their sub-filters for the socket when
  checks during the handshake are made.

HTTP/3 documentation on how https eyeballing works.

TLS improvements
- ALPN selection for SSL/SSL-PROXY filters in one vtls set of functions, replaces
  copy of logic in all tls backends.
- standardized the infof logging of offered ALPNs
- ALPN negotiated: have common function for all backends that sets alpn proprty
  and connection related things based on the negotiated protocol (or lack thereof).

Scorecard with Caddy.
- configure can be run with `--with-test-caddy=path` to specify which caddy to use for testing
- tests/tests-httpd/scorecard.py now measures download speeds with caddy

pytest improvements
- adding Makfile to clean gen dir
- adding nghttpx rundir creation on start
- checking httpd version 2.4.55 for test_05 cases where it is needed. Skipping with message if too old.
- catch exception when checking for caddy existance on system.

Closes #10349

tests/tests-httpd/testenv/httpd.py

@@ -69,22 +69,24 @@ class Httpd:
         self._error_log = os.path.join(self._logs_dir, 'error_log')
         self._tmp_dir = os.path.join(self._apache_dir, 'tmp')
         self._mods_dir = None
-        if env.apxs is not None:
-            p = subprocess.run(args=[env.apxs, '-q', 'libexecdir'],
-                               capture_output=True, text=True)
-            if p.returncode != 0:
-                raise Exception(f'{env.apxs} failed to query libexecdir: {p}')
-            self._mods_dir = p.stdout.strip()
-        else:
-            for md in self.COMMON_MODULES_DIRS:
-                if os.path.isdir(md):
-                    self._mods_dir = md
+        assert env.apxs
+        p = subprocess.run(args=[env.apxs, '-q', 'libexecdir'],
+                           capture_output=True, text=True)
+        if p.returncode != 0:
+            raise Exception(f'{env.apxs} failed to query libexecdir: {p}')
+        self._mods_dir = p.stdout.strip()
         if self._mods_dir is None:
             raise Exception(f'apache modules dir cannot be found')
+        if not os.path.exists(self._mods_dir):
+            raise Exception(f'apache modules dir does not exist: {self._mods_dir}')
         self._process = None
         self._rmf(self._error_log)
         self._init_curltest()
 
+    @property
+    def docs_dir(self):
+        return self._docs_dir
+
     def clear_logs(self):
         self._rmf(self._error_log)
 
@@ -213,9 +215,6 @@ class Httpd:
                 f'Listen {self.env.http_port}',
                 f'Listen {self.env.https_port}',
                 f'TypesConfig "{self._conf_dir}/mime.types',
-                # we want the quest string in a response header, so we
-                # can check responses more easily
-                f'Header set rquery "%{{QUERY_STRING}}s"',
             ]
             conf.extend([  # plain http host for domain1
                 f'<VirtualHost *:{self.env.http_port}>',