Use module attributes to store services strings.
Use display service name instead of hardcode it.
Use custom systray that ease the tooltip use.

- Create a custom SysTray that allows us to set services tooltips
independently.
- Initialize tooltip with service name at start.
- Update required service status on tooltip update.

[Closes #3998]
Use service's module strings instead of locals.
Merge remote-tracking branch 'ivan/bug/3998_shared-systray-tooltip' into develop
Check if we have a systray to use.

This fixes a failure when we run the first run wizard and don't have a
systray ready.
Merge remote-tracking branch 'ivan/bug/fix-systray-bug-in-first-run' into develop
Fix call to smtp gateway.