serve well-known client and server config

This way users can have a simpler time configuring this stuff and we can
worry about the spec compliance parts and specifying the same thing over
and over parts.

src/api.rs

@@ -2,3 +2,4 @@ pub(crate) mod appservice_server;
 pub(crate) mod client_server;
 pub(crate) mod ruma_wrapper;
 pub(crate) mod server_server;
+pub(crate) mod well_known;