Allow menu modification of SOON_THRESHOLD variable

[Kabboud]

Is your feature request related to a problem? Please describe.
No specific problem. Just an additional customization that would be appreciated and would remove the need to manually edit addon files.

Describe the solution you'd like
By default, OmniCC does not offer an option in settings to set the SOON_THRESHOLD variable that determines when an ability (in terms of remaining CD) turns a different color (default red). The default value for this variable in the "Addons\OmniCC\core\timer.lua" file is 5500, equivalent to 5.5 seconds. I would like to set this down to 3000 or 3 seconds. I've edited the file for now to achieve this, but it would be nice if this was something you could set in the in-game menu to avoid the value being potentially changed with addon updates.

Describe alternatives you've considered
N/A

Additional context
N/A