318 mosaic reorg

[mradamcox]

Implements the design updates that are described in #318. Also sets multimask to be powered by list of layers, rather than a specific layerset (more prep for #316).

Also a few other changes included:

• much-improved look of the details sections within the Map and Document/Region/Layers pages, which helps prepare for handling [Bug] When using dropdown to navigate pages download and web service links disappear #237
• layer.mask was causing errors in the IIIF annotation creation since moving masks to layers themselves
• add distrito federal as a state in the lookup in order to add mexico city (also had to patch the LOC parser to handle this)