Check if LumiBlock containers exist before recording
This MR solves the issue reported in !61980 (comment 6715716).
It is very rough, primarily to unblock https://its.cern.ch/jira/browse/ATLINFR-4934 without reintroducing a bug of not adding LumiBlockMetaDataTool
.
I'd like to polish it a bit (e.g. there's a lot of code duplication in all of this tool, not only this MR) in follow-up MRs.
/cc @calpigia