- Can pick a programmer if missing,
- Can auto-select a programmer on app start,
- Can edit the `launch.json`,
- Adjust board discovery to new gRPC API. From now on, it's a client
read stream, not a duplex.
- Allow `.cxx` and `.cc` file extensions. (Closes#2265)
- Drop `debuggingSupported` from `BoardDetails`.
- Dedicated service endpoint for checking the debugger.
Signed-off-by: Akos Kitta <a.kitta@arduino.cc>