Deprecate AdminLTE

As part of a recent Meteor update, the AdminLTE framework started giving errors. We discussed removing AdminLTE, since we are not using it very much. Go ahead and remove AdminLTE, and use the default layout for all settings views.

Locate the AdminLTE integration and the settings views in the repository, then inspect how those views select their layouts. Run the existing application checks or tests available for the settings UI before and after the removal. Done means AdminLTE is no longer used and every settings view renders with the default layout without Meteor errors.

Written by the indexing model from the issue text.