NERSC file item

See merge request !13

Includes "moving" NERSC directory item to the analysis tab

Also update NERSC file browser dialog to disable Apply button until
dialog fetches some path.

* Add autostart class to register ItemView
* Construct the UI widgets
* Add nersc-fileitem.sbt for internal testing
* Also update browser widget to set username field

* Includes example application for testing
* Also update plugin to check for SSL support

Rfpost workflow

See merge request !12

* smtk added active categories to resource
* project-manager updated to set them in export operator spec

* Omit superclass (BaseWriter)
* Add coaxPort logic
* Extend test case
* Update categories logic - still requires smtk update

* Add RFPostWriter class
* Add categories [Simulation, Rf-Postprocess] to operation template
* Make export model optional (using categories) in ace3p-export.sbt
* Make model optional in test-end-to-end.py