Reworking the board connection mechanism

[vshymanskyy]

I think of reworking the board connection mechanism:

1. Upon connection verify if user code is running (send Enter, see if REPL responds)
   • If REPL responds, automatically load system info and FS structure
2. If no REPL responce, check if user have selected the Interrupt Running Code setting
   • If no interruption is needed, stay in Terminal mode, disable FS and Editor temporarily until the code exits or is interrupted by the developer
   • If interrupting is needed, interrupt code, load FS contents

Also, I think auto-restart setting would be useful, that would soft-reset board when:

• initial connection interrupted the app execution
• user saves any file

But before that, I want to play a bit with aiorepl: #30

👉 feedback is welcome 👈