Automation - Github actions

[Baklap4]

Within the main repo we've added a bunch of automation for performous
It'd be nice to also apply the findings there to here and create faster releases and build checks.

Todo

• Add github workflow (copy paste from performous/performous)
• Add Nightly link to readme
• Add PR commenter (copy paste from performous/performous)
• Create buildscript for Windows
• Create buildscript for Linux
• Create buildscript for OSx
• Add CPACK within the main cmakelists (copy paste from performous/performous)
• Add uninstall target
• Windows - Make sure to install within Program Files/Performous/composer
  • this way the directory becomes:

  ProgramFiles/Performous/Performous/Performous.exe
  ProgramFiles/Performous/Composer/Composer.exe
  

• Add Github Issue forms

[Baklap4]

Couple of items are already done in latest master see PR #46

[Baklap4]

@twiecki please watch this issue for new windows binaries :)