build: fix ECH to always enable HTTPS RR

[vszakats]

The ECH feature cannot be built without HTTPS RR.

ECH automatically implied HTTPS RR in ./configure but not in CMake,
winbuild, documentation.

Also update documentation and CI configs.

Follow-up to a362962 #11922

[vszakats]

I'm casually considering this a bugfix.

[vszakats]

Any objections for merging this in the bugfix cycle?

The essence is lib/curl_setup.h activates USE_HTTPSRR
now instead of ./configure. The rest is CI and docs updates.

--- a/configure.ac
+++ b/configure.ac
@@ -5022,8 +5022,6 @@ if test "x$want_ech" != "xno"; then
 
   dnl now deal with whatever we found
   if test "x$ECH_ENABLED" = "x1"; then
-    dnl force pre-requisites for ECH
-    AC_DEFINE(USE_HTTPSRR, 1, [force HTTPS RR support for ECH])
     AC_DEFINE(USE_ECH, 1, [if ECH support is available])
     AC_MSG_RESULT($ECH_SUPPORT)
     experimental="$experimental ECH"
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -290,6 +290,14 @@
 #  define CURL_DISABLE_HTTP_AUTH 1
 #endif
 
+/*
+ * ECH requires HTTPSRR.
+ */
+
+#if defined(USE_ECH) && !defined(USE_HTTPSRR)
+#  define USE_HTTPSRR
+#endif
+
 /* ================================================================ */
 /* No system header file shall be included in this file before this */
 /* point.                                                           */