NXCALS-1924 added system + test + lomboked DataAccessField
#Merge request template @acc-logging-team - please have a look for approval.
features
- system added to java / scala variable builders
- system added to python variable builders (note the code change difference! If ever requested I can rewrite the java builders like I've done the python ones)
minor
- migrated DataAccessField to lombok + added one convenience method (hasAlias)
Closes NXCALS-1924