Feat: Add API

[lewislarsen]

Vanguard PR

Description

This adds an API to the application. Currently an initial implementation and it needs a bunch of refinement first.

i.e. There are way too many permission toggles, and missing key endpoints like running a backup task, backup schedules, log data etc. I'll be adding this soon, I wanted to get the "core" CRUDdy stuff of Vanguard implemented, and then work on refinement.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested both with automated tests and manual.

• Automated testing (Feature tests, Unit tests)
• Manual testing (explain the steps)

Checklist:

• I have performed a self-review of my own code
• My changes do not introduce any new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes
• I have used translation helpers and provided translations (where appropriate)

Screenshots (if applicable):