Update images in README and add building step for updating & fix services starting

See merge request !41

submodules

- Added music.youtube.com to handled URLs in non-playstore version
- Added open.spotify.com to handled URLs in non-playstore version
- Reverse portrait toggle when on now allows reverse portrait and when off will use last orientation rather than portrait.
- Added playlist video deletion confirmation dialog (with a setting to disable)
- Added a dialog showing the uploaded log id with a copy button

Autobackup password check, Filesize estimation int overflow fix, Deleting subscriptions part of subgroup fix, License delete confirm dialog, double check pager closed runtimes

Sync implementation for subscriptions, tracking subscription removals, add fcast link to cast tutorial description.

Sync protocol

See merge request !35