Add new GestureManagerDelegate method to track gesture progress

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## New Feature

We encountered problem that we cannot adjust or track gesture while it is in progress as we cannot track it. We suggest to add new method `func gestureManager(_ gestureManager: GestureManager, didChange gestureType: GestureType)`. It will allow to track gesture progress and update other views or map, if we want specific behaviour like zoom only to centre.

## Why
In mapbox 6 there was "regionIsChanging" delegate which we used and anchorPoint method for gestures where we could adjust centre point when user performs a gesture. In new version there no such methods or they are not as obvious to use. We need this, for example, to update angle slider when user rotate map with pinch gesture and also to update map centre while zooming with pinch so map won't move (forbid pan gesture while zooming)

Start by locating GestureManagerDelegate and the existing GestureManager and GestureType gesture callbacks. Determine how a progress-change callback should report pinch and rotation updates, then verify that consumers can use it to update views or the map center while a gesture is active.

Written by the indexing model from the issue text.