Copy maps between Macrostrat instances

[davenquinn]

We should be able to copy maps between Macrostrat databases (e.g., development, staging, production). A prototype of this functionality is available in the macrostrat maps sources copy command, implemented here. However, this is pretty limited.

It could be valuable to create an intermediate Geopackage file format to do the transfer. This would allow maps to be moved freely between Macrostrat instances and potentially create tools for people to prepare maps offline before sending them to Macrostrat proper (I could imagine encouraging geological surveys, StraboSpot users, etc. to do this).

This package could include:

• source map data
• metadata tables
• finalized map.<feature-type> table entries
• ingest_process information and tags as appropriate
  for an individual map.

Structurally, this could be based on the TA1 Geopackage library created during CriticalMAAS, for which we already have a basic writer as macrostrat import-criticalmaas which we've gotta change anyway.