Rework VSCode F5 Experience (L475)

Copied from @CIPop comments:

> I see the issue now. It's related to the mix of build / debug. /cc Dane
>
> F5 runs the tasks.json which do build and trigger OpenOCD to flash the device.
>
> Then Cortex-Debug starts which re-flashes the device a second time (also OpenOCD) but this time with launch.json and that one is the wrong file.
>
> We need to re-work that entire part to properly add all samples with debugging ability and remove the tasks.json dependencies which are already satisfied by F7 (CMake build integration with VSCode that allows selecting the projects, etc)