Add certificates flash command

[silvanocerza]

certificates flash command is used to flash certificates to the specified board connected on the specified address.

It supports four flags:

• --fqbn, -b, Fully Qualified Board Name, e.g.: arduino:samd:mkr1000, arduino:mbed_nano:nanorp2040connect
• --address, -a, Upload port, e.g.: COM10, /dev/ttyACM0
• --url, -u, List of urls to download root certificates, e.g.: arduino.cc:443
• --file, -f, List of paths to certificate file, e.g.: /home/me/Digicert.cer

Multiple urls or files can be specified to flash them at the same time.

Example commands:

FirmwareUploader certificates flash --fqbn arduino:samd:mkr1000 --address COM10 --url arduino.cc:443 --file /home/me/Digicert.cer
FirmwareUploader certificates flash -b arduino:samd:mkr1000 -a COM10 -u arduino.cc:443 -u google.cc:443
FirmwareUploader certificates flash -b arduino:samd:mkr1000 -a COM10 -f /home/me/VeriSign.cer -f /home/me/Digicert.cer