Prosody: new settings to provide a custom certificates dir

server/lib/diagnostic/prosody.ts

@@ -80,6 +80,14 @@ export async function diagProsody (test: string, options: RegisterServerOptions)
     }
     result.messages.push(`Room content will be saved for '${wantedConfig.logExpiration.value}'`)
 
+    if (wantedConfig.paths.certs === undefined) {
+      result.messages.push({
+        level: 'error',
+        message: 'Error: The certificates path is misconfigured.'
+      })
+      return result
+    }
+
     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, {