Steps for merging chains with common sequences in the HLT control flow

These changes cover:

• factorisation of sequences in the emulation test
• better organization and factorisation of the fast calo sequence
• factorisation of electron menu code
• added test for running the TriggerMenuMT generation with gamma chains
• some cleaning of the CF generation (touching all signature tests)
• bug fix for running electron and photons in fullMenu
• bug fix for MET L1 RoIs
• added MET chains in fullMenu

Tagging: @tbold, @sgeorge, @tamartin, @bernius , @damazio, @dbakshig