Require authentication to participate in chat (#4762)

* feat(chat): require authentication to participate in chat

* fix: it's pretty much impossible to bypass the auth requirement, addressing review feedback anyway

* feat(chat): render chat text input as disabled if chat auth is required

* Commit updated API documentation

---------

Co-authored-by: Owncast <owncast@owncast.online>

webserver/handlers/generated/generated-types.gen.go

@@ -1,6 +1,6 @@
 // Package generated provides primitives to interact with the openapi HTTP API.
 //
-// Code generated by github.com/oapi-codegen/oapi-codegen/v2 version v2.3.0 DO NOT EDIT.
+// Code generated by github.com/oapi-codegen/oapi-codegen/v2 version v2.5.1 DO NOT EDIT.
 package generated
 
 import (
@@ -918,6 +918,9 @@ type SetForbiddenUsernameListJSONRequestBody SetForbiddenUsernameListJSONBody
 // SetChatJoinMessagesEnabledJSONRequestBody defines body for SetChatJoinMessagesEnabled for application/json ContentType.
 type SetChatJoinMessagesEnabledJSONRequestBody = AdminConfigValue
 
+// SetChatRequireAuthenticationJSONRequestBody defines body for SetChatRequireAuthentication for application/json ContentType.
+type SetChatRequireAuthenticationJSONRequestBody = AdminConfigValue
+
 // SetChatSlurFilterEnabledJSONRequestBody defines body for SetChatSlurFilterEnabled for application/json ContentType.
 type SetChatSlurFilterEnabledJSONRequestBody = AdminConfigValue