Show notification while submitting forms

[seadowg]

There should be a notification shown during auto and background manual submits. The notification should have:

• subtext with project name
• Title text reading "Uploading forms..."
• Indeterminate progress bar

Notes

Given we're showing a notification we should make uploading a Foreground Service (which gives the task preferential treatment with scheduling, power use etc). We can do this with WorkManager now by calling setForegroundAsync from within a Worker (documented here). We'll probably need to make some additions to WorkAdapter and Scheduler (as well as implementations) to get that all to work.