Resolves#10953.
A refreshed UI for the 2.0 release. The existing "theming" is a bit long in the tooth and this PR attempts to give it a modern look and some freshness to compliment all of the new features under the hood.
The majority of the changes to UI have been done through updates to the Bootstrap theme contained in bootstrap-theme.css. These are simply overrides to the default stylings that are packaged with Bootstrap.
* Improve modal UX with logical form ordering, semantic form elements, visual hierachy tweaks
* make modal header prefix dynamic if SUBDAG
* Add heading as demarcation between action sections within modal
* Update doc screenshot w/ added modal heading
Ryan Hamilton
Patrick Cando
Kaxil Naik
Kamil Breguła