core: Refactor and improve listener logic (#5089)

* core: Refactor, improve listener logic

Deprecate:
- caddy.Listen
- caddy.ListenTimeout
- caddy.ListenPacket

Prefer caddy.NetworkAddress.Listen() instead.

Change:
- caddy.ListenQUIC (hopefully to remove later)
- caddy.ListenerFunc signature (add context and ListenConfig)

- Don't emit Alt-Svc header advertising h3 over HTTP/3

- Use quic.ListenEarly instead of quic.ListenEarlyAddr; this gives us
more flexibility (e.g. possibility of HTTP/3 over UDS) but also
introduces a new issue:
https://github.com/lucas-clemente/quic-go/issues/3560#issuecomment-1258959608

- Unlink unix socket before and after use

* Appease the linter

* Keep ListenAll

modules/caddyhttp/matchers.go

@@ -156,7 +156,9 @@ type (
 	MatchHeaderRE map[string]*MatchRegexp
 
 	// MatchProtocol matches requests by protocol. Recognized values are
-	// "http", "https", and "grpc".
+	// "http", "https", and "grpc" for broad protocol matches, or specific
+	// HTTP versions can be specified like so: "http/1", "http/1.1",
+	// "http/2", "http/3", or minimum versions: "http/2+", etc.
 	MatchProtocol string
 
 	// MatchRemoteIP matches requests by client IP (or CIDR range).