Add Uptake Telemetry

[leplatrem]

Send Uptake Telemetry events (using glean?):

If possible, mimic the current desktop events:

• 1% sample on esr & release
• category: "uptake.remotecontent.result"
• method: "uptake"
• component: "remotesettings"
• status: one of available statuses
• extra
  • "source": "{bucket}/{collection}"
  • "trigger": source of sync (eg. "manual", "timer", "broadcast", "startup")
  • "errorName": (optional) error classname
  • "duration": (optional) milliseconds (eg. pull changes, import changes, ...)