[src-dafus] Read signature on PowerOn

[3Nigma]

Study the possibility of integrating a signature at power-on and reporting it to acad every time a signature read by psale is requested. This will make the ale board not reset every time a signature request is made but it will also make the programmer not capable of reading the signature in real-time. I guess this shouldn't be much of a problem.

The other variant would be to move the psale mcu-checking from the code form and into the main form.