Add the OH version number to the filename for backups created with openhab-cli

[nelsonaponte]

To help the user easily identify the openHAB version backed up within a backup file, the filename of the file generated by the command openhab-cli backup should be as follows:

Current Format: openhab-backup-MM_DD_YY-HH_mm_ss.zip (e.g. openhab-backup-24_08_23-07_48_03.zip)
Suggested Format: openhab-backup-OHversion-MM_DD_YY-HH_mm_ss.zip (e.g., openhab-backup-4_1_3-24_08_23-07_48_03.zip), where the subdivisions of the openHAB version should be separated by the underscore ( _ ) character, e.g. 4.1.3 --> 4_1_3

https://github.com/openhab/openhab-distro/blob/main/distributions/openhab/src/main/resources/bin/backup