feat(bkgpslog):Include more fields in VERSION
These fields are included to automatically-generated VERSION file
included when a new tar is generated or the script is restarted:
- SCRIPT_VERSION : Version of bkgpslog being run.
- SCRIPT_NAME : Name of the script being run ("bkgpslog").
- SCRIPT_URL : URL where script can be downloaded.
- AGE_VERSION : Version of age (encryption program) used.
- AGE_URL : URL where age can be downloaded.
- DATE : Creation timestamp (ISO-8601).
- HOSTNAME : Hostname of device running script.
- PUBKEY_[n] : Pubkey string used by age to encrypt.