Remove libosmgpsmap

[dakk]

We are using libosmgpsmap only as a geo canvas for drawing our things, but the library is not well maintained.

We can:

• rewrite a custom widget in python to replace it, implementing only what we need (georeferencing and layer handling)
• fork the code and keep only what we need without useless deps and features
• fork the code and make optional features
• fork the code inside gww codebase, removing what we don't need; we can implement efficient things inside if we need