RIFT-15943 - Debug tab presented no content and download button broken

RIFT-15943 - Debug tab presented no content and download button broken
- the link eventDispatch was not working
— converted to link.click()
- cleaned up download
— removed prefix (no longer needed)
— postponed building download content till button pressed
- added isLoading support
— retrieving crash log from server can take some time
— display loading text on page when loading
— use loading component
- bit of code clean up
— formatting
— var -> let/const
— comments

Change-Id: I9aa154c115c5a8b73879347ecc6587595d4bd0fd
Signed-off-by: Bob Gallagher <bob.gallagher@riftio.com>