Admin improvements, 2018

[loppear]

Simple fixes:

• Delete button should confirm before operation. #24
• Option to move Delete button from actions to Edit screen #23
• Datatables list view should format first column as link to Edit #22
• Changes to make it easier to replace or customize admin templates. #28 ( Admin templates should use render not include for partials, and expose better names #27)

New additions:

• Data validation and conversion - error handling on edit screens
• De-emphasize individual edits - bulk data handling, round-trip import/export
• Incorporate nxus-worker-queue based data import
• Import exception handling, reporting, record-keeping (exception queue / audit log)

Shared dataset management

• Data summary / quality reporting built-in
• Customize transformations to application-specific models, model relationships
• Dataset post-processing - generating region estimates, scores

Larger questions:

• nxus-web controllers are a mess for overriding behavior, though AdminController is the archetype use.
• Should AdminController instead coordinate/encapsulate a number of controllers, separating list / edit / import / export for finer control?
• Do we need better support for non-model-based controllers / nav uses?