Map ingestion: added fields

[davenquinn]

Updating the ingestion pipeline is a good opportunity to consider whether the sources.<source_slug>_polygons (and lines, points) ingestion tables need to standardize a few more fields to fit new use cases.

One major thing we want to do a better job of in v2 is representing each map "in its own terms", i.e., with colors/symbology inherited from the source if it's provided (GEMS and other modern map databases contain this information in machine-parseable form).

Polygons

• color: Color of the legend item in the source
• legend_abbrev or similar: the key used to describe a legend item on the original map (Qal or similar)
• symbol: The FGDC or other symbol used to mark the polygon
• symbol_color: The color to represent the symbol overlay

All of these items should be able to be normalized into the legend table during map standardization.

Lines

Not clear that there are any fields we should add.

• certainty/covered to control eventual dashing of contacts?
• Line orientations (already implemented in Line orientations #123)

Also, though we haven't ingested contacts consistently in the past, we should start doing this if they are provided.

[davenquinn]

@amyfromandi want to make sure this stays on the radar as part of map ingestion updates.