Rewrite solution activate in python

[TeddyAndrieux]

Component:

'salt', 'cli', 'solutions'

Why this is needed:

Centralized CLI

What should be done:

MetalK8s solution activate command should be part of metalk8sctl python CLI

metalk8sctl solution activate <name> --version <version>

Version is not mandatory, if not provided then we use the latest one.

Implementation proposal (strongly recommended):

This command will have the same behavior as the current activate command from the solution bash script.

Except that it will be written in Python and should not use salt binaries at all, only interact directly with Salt using Python library (check design documentation about Centralized CLI for more detail).