Refacter code to use new ObjectType

[sarthyparty]

Proposed changes

Problem: We currently use the variable objType to refer to a client.Object's type (skeleton of an object). We also use the variable obj to refer to a full client.Object (object with fields filled out). However, in many parts of the codebase these two variables are used closely together and are both of type client.Object which can be a little confusing.

Solution: I created a new type called ObjectType and refactored the codebase to utilize it.

Closes #1456

Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

NONE

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 2 lines in your changes missing coverage. Please review.

Project coverage is 87.61%. Comparing base (b429f74) to head (34708f7).

Files	Patch %	Lines
internal/mode/provisioner/manager.go	0.00%	1 Missing ⚠️
internal/mode/static/manager.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2121   +/-   ##
=======================================
  Coverage   87.61%   87.61%           
=======================================
  Files          96       96           
  Lines        6694     6695    +1     
  Branches       50       50           
=======================================
+ Hits         5865     5866    +1     
  Misses        773      773           
  Partials       56       56           

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[kate-osborn]

Let's also use the new type in the following places:

• nginx-gateway-fabric/internal/mode/static/state/change_processor.go

  Line 117 in 3fafa2e

  isReferenced := func(obj client.Object, nsname types.NamespacedName) bool {

• nginx-gateway-fabric/internal/mode/static/state/change_processor.go

  Line 121 in 3fafa2e

  isNGFPolicyRelevant := func(obj client.Object, nsname types.NamespacedName) bool {

• nginx-gateway-fabric/internal/mode/static/state/changed_predicate.go

  Line 13 in 3fafa2e

  delete(object client.Object, nsname types.NamespacedName) bool

• nginx-gateway-fabric/internal/mode/static/state/changed_predicate.go

  Line 56 in 3fafa2e

  func (a annotationChangedPredicate) delete(_ client.Object, _ types.NamespacedName) bool { return true }

• nginx-gateway-fabric/internal/mode/static/state/changed_predicate.go

  Line 30 in 3fafa2e

  func (f funcPredicate) delete(object client.Object, nsname types.NamespacedName) bool {

@pleshakov or @bjee19 any other places we should update this type?

[bjee19]

@bjee19 any other places we should update this type?

looks good to me! couldn't find any other places, @sarthyparty good job on being thorough!

[kate-osborn]

LGTM 🚀

[bjee19]

🚀 🚀 🚀