Refactor RunTrigCostAnalysis script

Refactor RunTrigCostAnalysis to run Cost Analysis:

• use CompFactory
• split setting up components into functions
• search for HLT Menu in the current directory
• get input flags using ConfigFlags (can list multiple input files, comma separated)
• add useEBWeight and baseWeight flags for TrigCostAnalysis configuration
• read a run number from file metadata

as a follow up retrieving HLT Menu from the database via SMK will be added

Tagging @mark @tamartin