CLOUDP-303615: IPA - Update check if resource is singleton

[lovisaberggren]

Proposed changes

After discussions we have decided to slightly modify the check for if a resource is a "standard" resource or a singleton resource. For most resources, they will still be treated the same, but some resources will not be considered singleton anymore.

• The concept of a "standard" resource is gone, since the IPAs don't really reflect this
• A resource is either singleton or not, and if it's not, we would expect it to have the standard methods (and optionally custom methods)
• Modified the singleton resource check to also look at if there is a post in some cases, the logic is explained in this diagram
• Added checks for if a path refers to "collection of resources" or "a single resource" instead of "child" for example, since it actually means a nested resource. Helps us correctly evaluate paths/resources, and allows us to disregard some weird paths that probably should be custom methods if implemented today (for example /resource/{id}/something/verb)

Tests

• Updated tests for resourceEvaluation for checking for singleton resource, collection path or single path
• Updated tests

Follow up

• Add/remove exceptions that are not needed anymore or that are required now

Jira ticket: CLOUDP-303615

[lovisaberggren]

Converting to draft for now, will do some testing on exceptions

[yelizhenden-mdb]

❤️

[yelizhenden-mdb]

LGTM. High-value foundational work!