Add Cluster Support for Point Annotation Managers

[pjleonard37]

Fixes: #1475

This PR enables clustering on point annotation managers, achieving parity with the Android implementation. Developers using this feature will pass a set of ClusterOptions when creating a pointAnnotationManager. This will configure cluster options on the GeoJSON Source, create a series of circle layers for each level of clustering, and add a text layer to display the cluster count.

In addition, this PR creates a new example to demo this functionality and new unit tests.

https://user-images.githubusercontent.com/7976026/196284010-54c9890e-5c04-4a86-9216-c84a37a0e8f9.mp4

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• [X] Describe the changes in this PR, especially public API changes.
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