Command refactoring

[ddmler]

Hey!

Type: new feature | code quality

Link to issue: fixes #306 fixes #302

This pull request affects the following components (please check boxes):

• [x] Core
• [ ] Analyzer
• [ ] Compiler
• [ ] Control Flow Graph
• [ ] Documentation

In raising this pull request, I confirm the following (please check boxes):

• [x] I have read and understood the Contributing Guidelines.
• [x] I have checked that another pull request for this purpose does not exist.
• [x] I wrote some tests for this PR.

Small description of change:

• Add display of "used config file: ..."
• Add option to set a different config file and load the config for compile and printcfg commands
• Added AbstractCommand (first step, we could pull up more into this class)
• Remove blame command line option (it's still configurable in the config file)

[ovr]

LGTM, Thank you @ddmler 👍 🍰