bundled FirmwareUpdater; customizable name; faster data transfer rate

Previously the WifininaFirmwareUpdater script would had to be sourced from WifiNINA. It is now included in the examples of this project.

Previously the device was always called "testname". Now the name is chosen when starting up bluetooth.

Baudrate between SAM and NINA was increased. Now requests a 7.25 ms connection interval to have minimum latency.

Initial release

Can specify input and output characteristics on SAMD and start Bluetooth.

Missing features:

• Flashing Nina requires multiple steps: upload NinaPassthrough, nix-shell, make flash
• Performance hasn't been benchmarked. Nina is currently built in debug mode.
• Supports only a very small subset of BLE. Official library doesn't support encryption etc. either, though.