* Add logic to sort identities in the main identity list
* Add column headers to sortable identity fields
* Modify Identity Item renderer to use a grid to line up with main list column headers
* Add sort option and direction to settings
* Update sort logic to allow for ascending/descending sort
- Remove sort option from view state and just read directly from settings
- Add header separator to column headers
- Add Unicode arrows to indicate current sort direction
- Move repeated column header fields to style
* Refactor sort UI to use arrows indicating sort direction
Use shared size group between main window and identity item for name/status/services columns, use grid rows and column defs to possibly clean up header margins
* Update sort indicator from main window constructor so indicator is always present
Shift name column header to left
* Move main view model to new file, move sort logic to vm, bind sort ui to vm
tweak column header style
Christopher Britton