Add map in app, allow offline access to own observation data

[earthknight]

I requested something like this as a feature back in January 2020

• https://forum.inaturalist.org/t/show-my-past-observation-pins-when-marking-new-observations-on-map/9503/16

The last comment was the following:

@tiwane

We’ve made an issue for this functionality here: https://github.com/inaturalist/inaturalist/issues/2892