Builtin Prosody modules:

* initialize prosody modules folder
* comment on prosody modules licensing
* use mod_muc_http_defaults to set rooms properties and prevent unauthorized room creation WIP

server/lib/diagnostic/prosody.ts

@@ -23,6 +23,8 @@ export async function diagProsody (test: string, options: RegisterServerOptions)
 
     result.messages.push(`Prosody will run on port '${wantedConfig.port}'`)
 
+    result.messages.push(`Prosody modules path will be '${wantedConfig.paths.modules}'`)
+
     await fs.promises.access(filePath, fs.constants.R_OK) // throw an error if file does not exist.
     result.messages.push(`The prosody configuration file (${filePath}) exists`)
     const actualContent = await fs.promises.readFile(filePath, {