Migrate from master-branch to main-branch

[tkilias]

Background

• Github create by default main branches and using here master leads to confusion

Acceptance Criteria

• Change Githooks
• Change CI
  • Github Action
  • External Service
• Change Branch protection
• Change branch names

[Nicoretti]

I'll setup a main branch, once its done I will assign the ticket to @tkilias or @tomuben for switching it for the project. (Admin rights needed)

[Nicoretti]

@tomuben , @tkilias

• Change Githooks [✓]
• Change CI [✓]
  • Github Action [✓]
  • External Service
• Change Branch protection [✓/x] (within the git hoooks, but on Github there non where setup for any branch)
• Change branch names [✓]