Integrate tools from viur-tools into viur-cli

[phorward]

The Repository https://github.com/phorward/viur-tools contains further tools which could be implemented into viur-cli as well.

• csvimport.py is a generic CSV-importing tool => What about viur-cli import command for that?
• viur-2to3.py is a draft for porting projects from ViUR2 to ViUR3 => What about a viur-cli 2to3 command?

The other tools like updatedb.sh, copyblobs.py or copydb.py are only relevant to ViUR2 and should be ignored.

[Grashalmbeisser]

Due to viur-scriptor added in the viur-ecosystem i would propose to not implement the .csv importe as an cli tool and rather write a generalized scriptor-script instead.

[Grashalmbeisser]

Its already handled.