feat: Implements swagger API documentation

[gruyaume]

Description

Implements swagger API documentation. There is now a bottom navigation item named "API" that redirects to an automatically generated Swagger documentation. Currently, only the "Network Slice" endpoint is documented. The others will come in a different PR.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that validate the behaviour of the software.
• I validated that new and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.