websocket: add option to disable auto-pong reply

This adds another bitflag on CURLOPT_WS_OPTIONS (CURLWS_NOAUTOPONG) that
disables the default and automatic PONG reply in the WebSocket layer.

Assisted-by: Calvin Ruocco

Closes #16744

tests/data/test2312

@@ -0,0 +1,66 @@
+<testcase>
+<info>
+<keywords>
+WebSockets
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes" nonewline="yes">
+HTTP/1.1 101 Switching to WebSockets swsclose
+Server: test-server/fake
+Upgrade: websocket
+Connection: Upgrade
+Sec-WebSocket-Accept: HkPsVga7+8LuxM4RGQ5p9tZHeYs=
+
+%hex[%89%00]hex%
+</data>
+# allow upgrade
+<servercmd>
+upgrade
+</servercmd>
+</reply>
+
+#
+# Client-side
+<client>
+# for the forced CURL_ENTROPY
+<features>
+debug
+ws
+</features>
+<server>
+http
+</server>
+<name>
+WebSockets no auto ping
+</name>
+<tool>
+lib%TESTNUMBER
+</tool>
+<command>
+ws://%HOSTIP:%HTTPPORT/%TESTNUMBER
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol nocheck="yes">
+GET /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: webbie-sox/3
+Accept: */*
+Upgrade: websocket
+Connection: Upgrade
+Sec-WebSocket-Version: 13
+Sec-WebSocket-Key: NDMyMTUzMjE2MzIxNzMyMQ==
+
+</protocol>
+<errorcode>
+0
+</errorcode>
+</verify>
+</testcase>