Line orientations

[davenquinn]

Migration to create a lines_oriented column in the maps.sources table

• Allows status of map (whether its line orientations can be trusted) to be stored in the database
• Includes a data migration for several maps where we know lines are consistent

The overall structure allows us to define whether we should render a tick mark (e.g., for fault labels) on a given line.

Helps address UW-Macrostrat/web#267