Some minor fixes, to improve stability.
Fixes:
- remove sudo from dpkg call (unnecessary due to checking if the script runs as root)
- Remove quotes from tag which is pushed to GitHub
- clean up self updater
- Change displayed version name for emby from `release_name` to `release_tag`
- Change recommended installation method from pipsi (depricated) to [pipx](https://github.com/pipxproject/pipx).