Ubuntu virtualbox tokens and tags

[jspaaks]

• added check if user exists on server
• removed duplicate information 'remote_user' (now only uses ansible_user)
• added uninstall, restart, stop, start, enable, disable tasks that can be run using --tags

remaining open question, how to avoid having to ask for the personal access token a second time. Maybe store it in the remote machine? Update: I added reading from a file secrets.txt

[jspaaks]

After some discussion with @fdiblen, we identified these options for storing the PERSONAL_ACCESS_TOKEN:

1. don't prompt but have the user store it in hosts
2. don't prompt but have the user store it in ansible.cfg
3. don't prompt but have the user store it in a dedicated file, like token.env
4. prompt and store it on localhost
5. prompt and store it on the server

we thought 3 was the safest and most explicit option.

[jspaaks]

linter is now finally green (for this PR's playbook at least)