PHPStan prepare exceptions (#6037)

Take advantage of
https://phpstan.org/blog/bring-your-exceptions-under-control

Minimum changes to pass `tooWideThrowType` and `implicitThrows`.

Revert some mistakes from:
https://github.com/FreshRSS/FreshRSS/pull/5504
Preparation needed before new PRs of the same type:
https://github.com/FreshRSS/FreshRSS/pull/5962

Fix several wrong PHPDocs and catches:

> Method ... has ...Exception in PHPDoc @throws tag but it's not thrown.

> Dead catch - ...Exception is never thrown in the try block.

app/Controllers/userController.php

@@ -208,7 +208,11 @@ class FreshRSS_user_Controller extends FreshRSS_ActionController {
 		}
 	}
 
-	/** @param array<string,mixed> $userConfigOverride */
+	/**
+	 * @param array<string,mixed> $userConfigOverride
+	 * @throws Minz_ConfigurationNamespaceException
+	 * @throws Minz_PDOConnectionException
+	 */
 	public static function createUser(string $new_user_name, ?string $email, string $passwordPlain,
 		array $userConfigOverride = [], bool $insertDefaultFeeds = true): bool {
 		$userConfig = [];