enhance downloaded file naming

[pitts-mo]

Please consider enhanced file naming to label ELRS firmware downloads.

suggested naming:
ELRS - Version - Target - Region - Summary Config Label

examples for an RX firmware.bin.gz are:
ELRS-v3.5.3-happymodel.rx_2400.ep-FCC-default.bin.gz (FCC region specified)
ELRS-v3.5.3-happymodel.rx_2400.ep-FCC-bindphrase.bin.gz (FCC region and bindphrase specified -option for actual bind phrase in file name?)
ELRS-v3.5.3-happymodel.rx_2400.ep-FCC-custom.bin.gz (specified options other than just FCC and bindphrase)