Support launching a supported DAP client using the lldb-dap binary.
Currently, only the official LLDB-DAP Visual Studio Code extension is
supported. It uses the VS Code launch URL format.
Here's an example:
```
lldb-dap --client vscode -- /path/to/exe foo bar
```
This will open the following URL with `code --open-url`:
```
vscode://llvm-vs-code-extensions.lldb-dap/start?program=/path/to/exe&args=foo&arg=bar
```
Fixes#125777
