building on ubuntu 20.04 was causing issue with a too recent glibc for
some users dependent on ubuntu 18.04 or similar (elementary OS)
The issue arise as github action ubuntu-latest was upgraded recently too
ubuntu 20.04.
This fix forces the app to be built on ubuntu 18.04
Relates #1471
* Added build and release actions
* Added building instructions.
Updated electron builder to 23.2.3.
Fix unpacked directory not being removed correctly.
* Minor fix to build command
* Allow users to change install location on windows.
Added AppImage for linux.
* Fix artifact naming