Add "favorites" functionality for frequently changed cmake cache variables

### Brief Issue Summary

My workplace project is parametrized by two cache variables:
- the hardware identifier for which the firmware is built on
- the product identifier which controls enabled set of functionality

Having cmake variant for each identifier pair gets quickly out of hand, so having the dropdowns for both values on cmake sidebar, somewhere near project outline, is desired.

I could just go to cmake cache ui each time, but currently calling build tasks which set one of the vars or typing that in integrated terminal is faster, although the build task list also gets bigger and bigger, and terminal approach is not that discoverable for my workplace colleagues.

### CMake Tools Diagnostics

_No response_

### Debug Log

_No response_

### Additional Information

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