Bug 1107106 - Port system templates to use template literals +autoland

Current errors to resolve:
apps/system/js/activity_window.js: line 169, col 11, Missing semicolon. (ERROR)
apps/system/js/app_statusbar.js: line 20, col 11, Missing semicolon. (ERROR)
apps/system/js/browser_context_menu.js: line 80, col 11, Missing semicolon. (ERROR)
apps/system/js/browser_context_menu.js: line 79, col 9, 'id' is defined but never used. (ERROR)
apps/system/js/homescreen_window.js: line 167, col 11, Missing semicolon. (ERROR)

https://bugzilla.mozilla.org/show_bug.cgi?id=1107106