[ENH] DB fragment long-running jobs cleanup

[rksh]

• Building out a centralized ExecutorService
• Creating a one-at-a-time by job type threadpool for these long-running jobs (and a queue of waiting jobs)
• keeping uploads from happening while these are running
• Swapping out (deprecated) ProgressDialog for the progress panel we use for uploads
• Removing leaky definitions and replacing them with runnables for Backup-DB, Export GPX, and Export M8b tasks.
• updating layour for transfer panel
• Standardizing these pogress-publishing, long-running tasks

TODO: translate new strings! Getting this out there for review because it's gotten so large.

[rksh]

added language files and addressed feedback.