TLA chain name changes (ATR-20395, ATR-21594) and bug-fix for TLA photon (ATR-23448)

In the current MR we:

• changed JetDS position in jet chains (ATR-20395)
• added low-threshold L1Topo chain for potential end-of-fill / low lumi / early menu (ATR-20395)
• added test chain for TLA multijet from HH4b seed (ATR-21594)
• fixed issue on photon container threshold to be lower wrt the photon chain threshold to avoid problem in ATR-23448 (with @mmontell). This is a temporary fix for the chain we're testing, but will need a check that this does not happen when parsing the chain name, which will happen in a subsequent MR.

Update 23/05/2021: Fixing the multijet test chain, but also testing a single TLA stream for jets and photons. Update 23/05/2021: testing of a single TLA stream in its own branch, fixed multijet test chain Update 25/05/2021: fixing reference for multijet test chain, more edge cases for photon TLA