feat: grafana_organization module and simplify vars-structure

[Nemental]

• added community.grafana.grafana_organization task
• added community.grafana.grafana_organization_user task (disabled, because community.grafana 1.6.0 required)
  • removed in favor of feat: manage organization users #18
• fixed ansible role downloads badge
• fixed and beautify readme variables table
• minify yaml
• ⚠️ removed subelements('x_object') filter from several loops
  • I don't understand the benefit of this. In some places it isn't used at all and in other places it is only used for the name, although you can replace this with the key name. I'm also wondering why x_object is defined as a list.
  • For further support of x_object, I could leave the subelements there for now and set a default for name if it isn't defined.

[rndmh3ro]

Thanks for this PR, looks goot to me.

⚠️ removed subelements('x_object') filter from several loops

The idea behind this was that you could create several objects with the same configuration but only had to write the configuration once, e.g. like this:

grafana_teams:
  - team_object:
     - team_1
     - team_2
     users:
      - foo
      - bar

We initially did this in the icinga-director collection but the usage of it never really took off. So I'm fine with removing it. This however is a breaking change that we'll need to address.

[Nemental]

@rndmh3ro can you please take a look on this PR? :)
After the merge I can finalize #18 and merge it too. Thanks!