Add visible warning about impending license expiry

[RealRaven2000]

There is currently no visible warning before the quickFilters Pro license expires. Instead the user will be met with restricted functionality of the non-licensed product.

The only place the future expiry date (and an extend license button) is visible is if the user opens to the license tab in settings:

Therefore I propose we use the quickFilters toolbar button to communicate a near future expiry:

[RealRaven2000]

If the license expires within 10 days, quickFilters will now use a signal color (orange) and add the label "License expires in N days". It will also add a menu item "Check license status..." to the top of the menu to check the license status and enable the user to extend their license conveniently:

This will open the license tab where the expiry date can be checked and the [Extend License] be used to go to the web shop.

[RealRaven2000]

Implemented in v5.9 - Published 28/03/2023