Allow for execution on set change

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Is your feature request related to a problem? Please describe.

I have a script to update the controller LED's and I use those LED's to indicate what set I am on. I can do this via the advanced dialogue similar to https://github.com/AntiMicroX/antimicrox/issues/122#issuecomment-748119101, but it would be nice if I could inject something when a set becomes active. The biggest reason for this is so that it is always accurate.

I do not care for pop-ups and my GUI does not have a system tray so I would prefer to have the flexibility to implement my own notification system separate from #122.

The other benefit to doing it on set activation instead of on calling action is that it would work with while held sets, and again, always be accurate.

### Describe the solution you'd like

A settings option to allow for a custom set change notification, which includes binary and arguments. The arguments could include custom message text along with variables %n for set number, %s for set name, %p for profile name, %c for controller name, and possibly others for vid:pid, index, ....

I assume that there would be an option to turn off notifications as proposed in #122. This setting could be coupled with that option in the settings dialogue.

### Describe alternatives you've considered

I also considered that it might be nice to allow for more than just an execution action. e.g. maybe one could trigger a macro or key that makes the set useful in the first place. Essentially, front loading a set change with most all of the options available in the new key assignment dialogue. Obviously not allowing for a set change on set change or similar ludicrousness. My fear there is how to implement it without making the GUI obnoxious.

### Additional context

_No response_