.NET MAUI maps custom vector map capability

### Description

To be able to use maps inside factories, hospitals, zoos, etc. you need their specific map with some custom items rather than Google maps which only have roads, buildings and mountains.

When using custom map, you have to provide GPS coordinates of the custom map and then it can be used.
This is possible with third-party control vendors in desktop applications already such as DevExpress and is extremely powerful.

### Public API Changes

Instead of Google maps provider, use custom map provider.

### Intended Use-Case

To be able to use maps inside factories, hospitals, zoos, etc. you need their specific map with some custom items rather than Google maps which only have roads, buildings and mountains.

Start by reviewing the current Google maps provider and the proposed public API change. Determine how a custom vector map provider would accept GPS coordinates and expose custom map items for factories, hospitals, and zoos; done means custom maps can be used instead of Google maps.

Written by the indexing model from the issue text.