Clean up well-known routes/controllers (#1649)

* Add request spec for host meta route returning xml

* Add routing spec for xrd routes

* Update well-known routes

* Move webfinger and host-meta actions to their own controllers

app/controllers/well_known/host_meta_controller.rb

@@ -0,0 +1,13 @@
+  # frozen_string_literal: true
+
+module WellKnown
+  class HostMetaController < ApplicationController
+    def show
+      @webfinger_template = "#{webfinger_url}?resource={uri}"
+
+      respond_to do |format|
+        format.xml { render content_type: 'application/xrd+xml' }
+      end
+    end
+  end
+end