Selective persistence of detector RawBanks at line level

Selective persistence of detector RawBanks is currently at the stream level.

For instance all lines in stream A will have the same detector RawBanks persisted.

In Run 2 this could be done at the line level. Each line should define the detector RawBanks it wants to persist

At HLT2 this is blocked by #321 (closed)

cc @rmatev @mvesteri