Add 'publish encoding keys' functionality
During testing caused lhcb-conddb/file-content-metadata!109 (closed)
Thanks to tevans, this is based mostly off of /group/hlt/commissioning/publish_encoding_keys.sh
per https://gitlab.cern.ch/lhcb-rta/piquet-guide/-/wikis/HLT-piquet-guide/HLT1#publishing-decoding-keys-for-hlt1-stacks.
Edited by Luke Grazette