Backend routing brainrack

[peppidesu]

For the backend, we should start to think about how we organize our endpoints. Here are some considerations:

• should the install endpoint be at the top level, or organized below /addon(s)?
• should we have a separate endpoint for getting a single item from a table by ID (e.g. getting a single addon), or have it be the same as getting multiple ones and instead have it be a json option?
• what is going to be the overall layout of our routes (birds-eye view)?

[peppidesu]

To clarify the second point, we could have the following ways to get an addon by ID:

• GET /api/addons, providing an optional ID field in the JSON body
• GET /api/addons?id=xyz providing an optional ID field in the query
• GET /api/addons/xyz, having the ID be part of the URL

[peppidesu]

@stickyPiston @Tjalle-S