Clean up of usage of hlt1_tracking in Hlt2 lines

Move functions like require_pvs and require_gec in a dedicated module event_filters as neither of them actually uses Hlt1 information.

Also moved default_ft_decoding_version to a new module called decoders.

Old code won't break but will give deprecation warnings.

Required changes for people

#from RecoConf.hlt1_tracking import require_pvs, require_gec
from RecoConf.event_filters import require_pvs, require_gec

#from RecoConf.hlt1_tracking import default_ft_decoding_version
from RecoConf.decoders import default_ft_decoding_version

Needs MooreAnalysis!79 (merged)

Needs Alignment!249 (merged)