Improvement: add raster mbtiles standard format on the map

[gignacnic]

Add raster mbtiles as overlay layers on the map by the user, like it can be done in other GPS navigation app products similar to OsmAnd (ex. Locus Map), would it be a big features to develop if the user would be able to add mbtiles (standard raster format) on the map? I know that this translator exist: https://github.com/tarwirdur/mbtiles2osmand/blob/master/mbtiles2osmand.py, but it is not as straight forward as other GPS navigation app.

[gignacnic]

If there is a simple way to pay for this development, I would look at contributing $.

[vshcherb]

I'm afraid if we're going to outsource this feature development it could be quite expensive to build.

[aricooperdavis]

I'd also be interested in this, it should be relatively straightforward as the SQlite formats are very similar. I believe this is a duplicate of #3673

[aricooperdavis]

@vshcherb can we get this issue closed in favour of #3673?