Merge #4366

4366: Unified debug lens r=matklad a=vsrs

Right now every debug engine gets the debug executable and exports the errors on its own.

This PR unifies the way all engines work. And adds an option to configure each engine separably.
For example, this adds visualizers for both `CodeLLDB` and `C++ tools Windows debugger`
```json
"rust-analyzer.debug.engineSettings": {
    "cppvsdbg": {
        "visualizerFile": "${workspaceRoot}/rdisk.natvis"
    },
    "lldb": {
        "initCommands": [
            "command script import ${workspaceRoot}/rdisk.vis.py"
        ]
    }
}
```

Co-authored-by: vsrs <vit@conrlab.com>
Co-authored-by: vsrs <62505555+vsrs@users.noreply.github.com>