https-rr: implementation improvements

- fold DoH and async HTTPS-RR handling into common code.
  have common cleanups, etc. Have a CURLcode result in async
  handling to allow HTTPS RR parsing to fail.
- keep target, ipv4hints, ipv6hints, port and echconfig also
  when resolving via cares. We need to know `target` and `port`
  when evaluating possible ALPN candidates to not go astray.
- add CURL_TRC_DNS for tracing DNS operations
- replace DoH specific tracing with DNS, use doh as alias
  for dns in curl_global_tracea()

Closes #16132

lib/httpsrr.h

@@ -35,6 +35,8 @@
 #define CURL_MAXLEN_host_name 253
 #define MAX_HTTPSRR_ALPNS 4
 
+struct Curl_easy;
+
 struct Curl_https_rrinfo {
   /*
    * Fields from HTTPS RR. The only mandatory fields are priority and target.
@@ -53,7 +55,15 @@ struct Curl_https_rrinfo {
   uint16_t priority;
   bool no_def_alpn; /* keytag = 2 */
 };
-#endif
+
+CURLcode Curl_httpsrr_set(struct Curl_easy *data,
+                          struct Curl_https_rrinfo *hi,
+                          uint16_t rrkey, const uint8_t *val, size_t vlen);
+
+struct Curl_https_rrinfo *
+Curl_httpsrr_dup_move(struct Curl_https_rrinfo *rrinfo);
+
+void Curl_httpsrr_cleanup(struct Curl_https_rrinfo *rrinfo);
 
 /*
  * Code points for DNS wire format SvcParams as per RFC 9460
@@ -68,9 +78,12 @@ struct Curl_https_rrinfo {
 CURLcode Curl_httpsrr_decode_alpn(const unsigned char *cp, size_t len,
                                   unsigned char *alpns);
 
-#if defined(USE_ARES) && defined(USE_HTTPSRR)
+#if defined(USE_ARES)
 void Curl_dnsrec_done_cb(void *arg, ares_status_t status,
                          size_t timeouts,
                          const ares_dns_record_t *dnsrec);
-#endif
+
+#endif /* USE_ARES */
+#endif /* USE_HTTPSRR */
+
 #endif /* HEADER_CURL_HTTPSRR_H */