Add support for multiTriggerChainsPerYear in TriggerAnalysisBlock

Proposal to add support to store separate trigger scale factors for analyses implementing trigger bucket strategies of the type:

If leading lepton pT>XX, check single lepton trigger / else check di-lepton trigger.

The argument multiTriggerChainsPerYear would then be set to something like

Trigger:
    multiTriggerChainsPerYear:
        'SLT':
            '2015':
               - 'HLT_mu26_ivarmedium'
            '2016':
               - 'HLT_mu26_ivarmedium'
            '2017':
               - 'HLT_mu26_ivarmedium'
            '2018':
               - 'HLT_mu26_ivarmedium'
        'DLT':
            '2015':
               - 'HLT_2mu14'
            '2016':
               - 'HLT_2mu14'
            '2017':
               - 'HLT_2mu14'
            '2018':
               - 'HLT_2mu14'

The current default config based on https://gitlab.cern.ch/atlas/athena/-/blob/main/PhysicsAnalysis/Algorithms/AnalysisAlgorithmsConfig/data/example_config.yaml#L104 would still be supported

FYI @tadej @ravinab @krumnack