[RTADPA BW Tests] Upload the metadata yaml from nominal hlt2 bw tests, so that it can be accessed later by sprucing bw tests

related to lhcb-datapkg/PRConfig!361 (merged) + lhcb/Moore!2763 (merged) + LHCbNightlyConf!1121 (merged)

Needs the xdrcp -f flag to overwrite an existing file, as discussed in !269 (comment 7351299).

• Resolved by !271 (merged)

ToDo:

• Rebase to include -f flag

Ready when upstream changes are done.