Use the TestFileDB everywhere instead of hardcoded paths on eos

Depends on lhcb-datapkg/PRConfig!484 (merged)

A reference update is needed for the following tests:

• Allen.mdf_input
• Allen.mdf_input_v3
• Allen.mdf_input_v4

These are all a result of more appropriate geometry or conditions versions being used. For the _vN tests the change is very minimal. For the mdf_input test the changes look good to me.