feat: use lazy app config values and small fixes

- use `isEnabledForAnyone` instead of `isInstalled` to check for app_api
- type annotations for both OCP and the OCA IContentProvider
- make `indexed_files_count` app config non-lazy

Signed-off-by: Anupam Kumar <kyteinsky@gmail.com>

Author: kyteinsky

lib/Logger.php

@@ -34,7 +34,6 @@ public function __construct(
 
 	public function getLogFilepath(): string {
 		$default = $this->config->getSystemValue('datadirectory', \OC::$SERVERROOT . '/data') . '/context_chat.log';
-		// todo: Legacy way was appconfig, now it's paralleled with the normal log config (?)
 		return $this->appConfig->getAppValueString('logfile', $default, true);
 	}