Configuration tweaks (#2567)

This makes the following changes:

* The various `Defaults` functions are now responsible for setting sane defaults if `generate` is specified, rather than hiding them in `generate-config`
* Some configuration options have been marked as `omitempty` so that they don't appear in generated configs unnecessarily (monolith-specific vs. polylith-specific options)
* A new option `-polylith` has been added to `generate-config` to create a config that makes sense for polylith deployments (i.e. including the internal/external API listeners and per-component database sections)
* A new option `-normalise` has been added to `generate-config` to take an existing file and add any missing options and/or defaults

federationapi/federationapi_keys_test.go

@@ -75,7 +75,10 @@ func TestMain(m *testing.M) {
 			// Draw up just enough Dendrite config for the server key
 			// API to work.
 			cfg := &config.Dendrite{}
-			cfg.Defaults(true)
+			cfg.Defaults(config.DefaultOpts{
+				Generate:   true,
+				Monolithic: true,
+			})
 			cfg.Global.ServerName = gomatrixserverlib.ServerName(s.name)
 			cfg.Global.PrivateKey = testPriv
 			cfg.Global.JetStream.InMemory = true

federationapi/federationapi_test.go

@@ -263,7 +263,10 @@ func testFederationAPIJoinThenKeyUpdate(t *testing.T, dbType test.DBType) {
 func TestRoomsV3URLEscapeDoNot404(t *testing.T) {
 	_, privKey, _ := ed25519.GenerateKey(nil)
 	cfg := &config.Dendrite{}
-	cfg.Defaults(true)
+	cfg.Defaults(config.DefaultOpts{
+		Generate:   true,
+		Monolithic: true,
+	})
 	cfg.Global.KeyID = gomatrixserverlib.KeyID("ed25519:auto")
 	cfg.Global.ServerName = gomatrixserverlib.ServerName("localhost")
 	cfg.Global.PrivateKey = privKey