Have only one object of the API and inject elsewhere

[ScreamingDev]

The issue was that multiple invocations of one class lay around which took to long to maintain. Therefor it is shifted into a service container so that we have it only one time in a central place.

• Except for tests.
• Inner api key logic is therefor removed as the container takes care of this.

Please read the commit messages for details.

Things to review

Common things:

• [x] Works fine.
• [x] Changelog written or not needed.
• [x] In case of bugfix also merged in other minor versions.
• [x] No conflict with current branch.

Got an idea while looking at the GUI? Please add a new issue refering to this one.

[andrecedik]

You should add a changelog entry.

[ScreamingDev]

Good to merge @andrecedik