IDE debugging

[luxas]

Capturing context from @twelho in #3 (comment):

The VS Code integration for probe-rs is documented here, while the actual integration plugin only has one very alpha release from many months ago in https://github.com/probe-rs/vscode/releases. In its current state it's not very user friendly in terms of debugging the integration itself, simply nothing happened when I tried launching the example project at https://github.com/probe-rs/vscode/tree/master/debug_example, with no logs to figure out what's wrong, and I didn't have time to debug it further. The "standardized" GDB side of affairs with cargo embed seems to work fairly well, and we might add some examples here at some point for IDE configuration, but right now it's out of scope.

Most people should not need to use a debugger here, probe-run provides fast debug prints and complete stack backtraces for panics. Rust itself avoids many of the oddities and bugs you would need a debugger for as well, but I'm presenting the option for those that know how to use GDB to start the server in an easy way. If you need to do that then the GDB CLI is pretty much your best (non-hacky) bet right now for adding breakpoints in the execution and watching variables.

Once things stabilize, and there is a greater need, we can revisit the options of

a) integrating with something like VS code and their specific debugging format directly or
b) integrating IDEs (possibly through extensions) to target the gdb server provided by cargo embed