Remove unused Parsedown.php (replaced by league/commonmark in Phase 1); update phpstan baseline

phpstan-baseline.neon

@@ -12,18 +12,6 @@ parameters:
 			count: 1
 			path: app/src/Dispatcher.php
 
-		-
-			message: '#^Unsafe usage of new static\(\)\.$#'
-			identifier: new.static
-			count: 1
-			path: app/src/Parsedown.php
-
-		-
-			message: '#^Variable \$text might not be defined\.$#'
-			identifier: variable.undefined
-			count: 2
-			path: app/src/Parsedown.php
-
 		-
 			message: '#^Offset ''channel_name'' on array\{instance_url\: string, username\: string, password\: string, channel_name\: string, privacy\: int, peertube_video_label\: string, peertube_audio_label\: string\} on left side of \?\? always exists and is not nullable\.$#'
 			identifier: nullCoalesce.offset