Implement the Composite Filter class

[cherylEnkidu]

#no-changelog

• Implement the Composite Filter class.
• Perform parsing of AND/OR filters to create Composite Filter objects.
• Add filter validation for composite filters.
• Update core/query and api/query_core to handle composite filters.

[google-oss-bot]

Size Report ¹

Affected Products

• FirebaseFirestore

  Type	Base (cc9c626)	Merge (8c364ec)	Diff
  CocoaPods	6.96 MB	6.97 MB	+17.3 kB (+0.2%)

Test Logs

• Base (cc9c626): https://github.com/firebase/firebase-ios-sdk/actions/runs/2883320066
• Merge (8c364ec): https://github.com/firebase/firebase-ios-sdk/actions/runs/2884858888

1. https://storage.googleapis.com/firebase-sdk-metric-reports/ImofORwVOL.html

[google-oss-bot]

Coverage Report ¹

Affected Products

• FirebaseFirestore-iOS-FirebaseFirestore.framework

  Overall coverage changed from 88.59% (cc9c626) to 88.48% (8c364ec) by -0.11%.

  Filename	Base (cc9c626)	Merge (8c364ec)	Diff
  composite_filter.cc	?	50.00%	?
  field_filter.cc	90.18%	93.44%	+3.26%
  FIRQuery.mm	88.00%	87.69%	-0.31%
  leveldb_index_manager.cc	97.57%	97.58%	+0.01%
  leveldb_key.cc	98.33%	98.63%	+0.29%
  query_core.cc	96.20%	96.26%	+0.06%
  target.cc	95.77%	95.85%	+0.08%

Test Logs

• Base (cc9c626): https://github.com/firebase/firebase-ios-sdk/actions/runs/2883320066
• Merge (8c364ec): https://github.com/firebase/firebase-ios-sdk/actions/runs/2884858888

1. https://storage.googleapis.com/firebase-sdk-metric-reports/rN4pNLRPm9.html

[ehsannas]

The way the "operator" for composite filters was defined was by re-using the proto definition. It was cumbersome and inconsistent with what was done for field filters. I've made a PR (https://github.com/firebase/firebase-android-sdk/pull/3824) to fix this. Please update this PR to do the same thing. I should have made this fix earlier. Sorry for the delay.