Add support for Firestore Enterprise Pipeline Queries

Firestore has recently launched Pipeline operations in Enterprise edition.
These powerful queries allow for complex transformations, aggregations, and
filtering that go beyond what Core operations currently support.

It would be beneficial for AngularFire to provide wrappers
for Pipeline operations to maintain parity with the Firestore JS SDK and
provide a better Angular developer experience.

In my opinion, the ability to perform searches using regex is the most important feature.

Has a date already been set for implementation?

Thanks for your work.

まず、AngularFire に既に存在する Firestore ラッパーと、Firestore JS SDK の Enterprise Pipeline Queries API を確認します。正規表現検索を含む、サポートされている Pipeline 操作を確認し、その後 Angular との同等性に必要なラッパーの公開 API を定義します。サポートされている操作が公開され、適切なテストでカバーされていれば完了です。

索引モデルが issue の本文から書いたものです。