This PR improves existing tests for ID obfuscation by:

• asserting on obfuscated IDs in returned links
• adding support for atomic operations
• using long instead of int as the internal ID type

ResourceGraphBuilder now has a Remove method, which enables the removal of a resource type from the resource graph, after assembly scanning has run. This is used to exclude the ObfuscatedIdentifiable abstract base class, which is not supposed to be exposed externally.

A new annotation [HideResourceIdTypeInOpenApi] is added to the JsonApiDotNetCore.OpenApi.Swashbuckle package, which can be used to hide the underlying type of IDs. Before, the OpenAPI schema looked like:

"schema": {
  "minLength": 1,
  "type": "string",
  "format": "int64"
}

With the new annotation added to ObfuscatedIdentifiable (which implicitly applies to all derived types), it becomes:

"schema": {
  "type": "string"
}

This is useful in the case of ID obfuscation because while the internal resource ID types are long, the publicly exposed obfuscated IDs are strings. We shouldn't make the internal ID type (which is an implementation detail) externally observable.

Closes #1067, closes #1603.

QUALITY CHECKLIST

• Changes implemented in code
• Complies with our contributing guidelines
• Adapted tests
• N/A: Documentation updated