Use records for joined resource Classes

[lgebhardt]

resolves #1308

In addition this PR also adds some details about the relationship to the join_details as each join is setup and tracked. This is useful if you need to override the apply_joins method and need a window into the details as each join was setup. This was originally intended for the some experiments with the jsonapi-authorization gem, but I believe it could prove useful in any case where a better window into the join process is needed.

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