Adds snap plug to grant access to ~/.config/aacs

Modifies the snap package so you can grant access to ~/.config/aacs which is needed for playing Blurays with a KEYDB.cfg file, fixing #28017 (closed)

Connect the new plug with snap connect vlc:dot-config-aacs.

The startup script also creates a symlink to the real AACs directory inside $HOME to the container inside $HOME/snap/vlc/current/