Support for custom resource URLs

[judgeaxl]

Is your feature request related to a problem? Please describe.

Not all JSON:API servers implement resource routes using the type name as is. Most common deviation seem to be using pluralized routes and singular types, .e.g. "type": "author" vs /authors`.

For most part links are discovered through server responses, but if you want to create a new resource, or for your initial "get", there's no way at the moment to specify an alternate route.

Describe the solution you'd like

Instead I propose to add another property route to JsonApiResourceOptions which can be used to generate resource URLs where needed. If route is defined, use it for link generation, otherwise fall back to the type name as it does now.

Describe alternatives you've considered

While it might be tempting to add an optional strategy for automatic pluralization, I think it miss the point. JSON:API doesn't require routes to follow the type names, so it would only partially solve the problem.

Additional context