[5.2] Refactor relations and scopes

[acasar]

As discussed on Slack, I refactored some stuff that was recently made overly complex by some pull requests. All in all, I managed to shave off around 100 lines of code and all tests still pass. I didn't touch any public methods so this shouldn't break anything.

Summary of scope refactoring:

• I merged applyCallbackToQuery and callScope in a single more general method called callScope
• I generalized mergeModelDefinedRelationWheresToHasQuery, made it public, and renamed it to mergeModelDefinedRelationConstraints so it can now be used from relations as well.
• I managed to greatly simplify applyScopes (which applies global scopes) by utilizing the new callScope method. As a result the applyScope helper method is not needed any more.
• Some minor refactoring of getGlobalScope on the Model to match the logic of withoutGlobalScope on the Builder.

Summary of morphTo refactoring:

• getEagerLoadsForInstance was deleted and replaced with a call tonestedRelations on the Builder (which is now public).
• mergeRelationWheresToMorphQuery was deleted as well. The new public Builder method mergeModelDefinedRelationConstraints is used instead.

Summary of SoftDeletes refactoring:

• I deleted withTrashed and onlyTrashed static helpers from the SoftDeletes trait, since the call is redirected to query macro anyway.

[taylorotwell]

Thanks ❤️

[lemesdaniel]

Hello,

@acasar, How do I recover deleted records now? Before I used onlyTrashed?

Thanks

[acasar]

@lemesdaniel exactly the same as before. If you're having any problems let me know.