Implement templates api

[ThomasRedpanda]

Documentation: https://apidocs.basekit.com/api-reference/templates/

Module

• Add a TemplatesApi module to the Api namespace.
• Add the module to the BaseKit class.

Endpoints:

• get templates
• get template categories

When implementing the endpoints, make sure to include links to the documentation using the @see annotation in the docblocks.

Testing

• Add tests for all the added domain objects
• Add tests for the added endpoints