Bug 811860 - Add sound notification to sent message
(cherry picked from commit 5d40e508df9fe61018a3e45749a1957fe886a1a1)

Conflicts:
	apps/settings/index.html
	apps/settings/locales/settings.en-US.properties
	apps/sms/js/thread_ui.js
	build/settings.py
Merge pull request #8258 from KevinGrandon/bug_811860_sms_audio_perf

Bug 844205 - [SMS] Regression in startup time r=borjasalguero(cherry picked from commit d427c60fd9692573297ba27845bd5f67b5c8fb54)