[RTA/DPA BW Tests] 'Aggressive' Sprucing compression settings in BWTests

Part of lhcb-datapkg/PRConfig#19, needed by Moore!3795

Compression settings to be configurable via options (thus Gaudirun) rather than only in Options (i.e. lbexec)

ToDo:

• Sign off from someone relevant/ more involved with PyConf
• Downstream checks Moore!3795