dar-backup v2 beta v. 0.6.21 released

[per2jensen]

This is (primarily) a documentation fix & update release 🎉

Doc highlights:

• installation instructions were missing the python3-venv package (bommer!)
• the --selection option to dar-backup now better explained
• the signing documentation now in collasible sections
• some spelling errors
• Not CPL 3, but GPL 3 license ! 😬

Installer:

• A new installer has been added:
• Create directories from a provided dar-backup.conf file (made by the user)
• Optionally also create catalog databases from backup definitions

I think this is the last release in the 0.6.x series.

I will probably bump the version number to 0.7.1 for the next one and do not expect many changes before the 2.0 version (as a 1.x bash based version exists)

---

This discussion was created from the release dar-backup v2 beta v. 0.6.21 released.