[Code health] Handle visibility of custom views from within VM

[shobhitagarwal1612]

Visibility of FeatureRepositionView and PolygonDrawingView could be handled in a better manner.

Current:

User action --> Set state to "completed" (CustomViewModel) --> Subscribe to state change in "MapContainerFragment" --> Set mode to DEFAULT, MOVE_POINT, DRAW_POLYGON (in MapContainerViewModel) --> Subscribe to mode in "HomeFragment" and update visibility of custom view.

Proposed:

User action --> Add LiveData for visibility (in CustomViewModel) --> Update visibility of custom view either using data binding or in CustomView.

Pros:

• Removes extra enum class "Mode"
• Prevents storing internal state of views in external classes

[gino-m]

@hemanp tried view bindings here, as did I, and for some reason couldn't get them to work. More work is needed here.

[gino-m]

@shobhitagarwal1612 Could you PTAL? Please assign back if you won't have cycles for this in Mar/Apr.

[shobhitagarwal1612]

This is irrelevant as all tasks are moved to a separate fragment.