Integrate map staging commands into this repository

[davenquinn]

Part of the map staging scripts should be pulled into this repository, so that we centralized the capabilities of uploading and tracking datasets.

This is part of #25.

• We should only pull in the "easily generalized" part of the map staging process. (We don't need web-scraping code here for NBMG or other sites).
• The core operations of "upload files and associate with a map entry" should be housed here.
• Maybe the less standard parts (web-scraping scripts, and the like) can be housed in a map-bulk-ingestion repository (or similar) where we record notes and scripts required to capture random maps? Maybe we can revive the UW-Macrostrat/map-ingestion repository to this purpose?

[brianaydemir]

I think I did the bulk of this work on https://github.com/UW-Macrostrat/macrostrat/pull/43.