Feature/socket keyboard

[georgik]

Add support for keyboard via tcp socket

[georgik]

The implementation requires 3 threads:

• emulator thread
• server socket thread for accepting new connection
• client handler thread to process data from client

How it works:

• emulator connects to WiFi configured in cfg.toml and opens port 80
• client can connect from computer by Netcat: nc IP-addr 80
• client can send keystokes like 10p"Hello"ENTER which is translated to 10 PRINT "Hello"ENTER
• keystrokes from client handler thread is passed via std::sync::mpsc::{channel, Sender, Receiver}; to emulator thread, this seems to be very reliable even when consumer is very slow like in this case
• note: Netcat sends data only on Enter key, if you need to send data earlier just press CTRL+D to flush the buffer

This is initial sketch and it's in working state. For merge it would be beneficial to mark the network dependent part as separate feature which can user enabled during the build.

[georgik]

Few notes from refactoring

• embedded-svc must be fixed to older version, because of SPI no longer works after update from v0.30 -> v0.37 esp-rs/esp-idf-hal#79
• when reference to WiFi goes out of scope, the WiFi is automatically disconnected
• tcp listener should be created inside new thread instead of passing from main thread to avoid problems with ownership

[georgik]

@SergioGasquez @MabezDev @bjoernQ @jessebraham Please review the code.
This change introduces tcpstream_keboard which allows to pass keystrokes via open TCP Socket using Netcat.
There are some challenges discovered during refactoring mentioned above.

[SergioGasquez]

Does using AuthMethod::None work on WPA2 networks? Maybe we could do some checks like in Ferrous System's repo

[bjoernQ]

when reference to WiFi goes out of scope, the WiFi is automatically disconnected

I think it's a sane decision in esp-idf-svc to shut down WiFi when it gets dropped