Fix serverinfo representation in nextcloud OCC command tool: add info…

[acomdigital]

This PR adds a new OCC command, as described in issue #190, to retrieve serverinfo data.
Fixes #190

Changes Made:

• Added occ command php occ serverinfo:info;
• Encapsulated some business logic of ApiController into a dedicated service layer

[github-actions]

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[kesselb]

Thanks for your pull request 👍

Sorry, I didn't have the opportunity to review it.

• DCO, Linter and Tests are failing.
• I'm unsure about adding another service to wrap the other services.