Draft: Add eta-dependence to legacy tau thresholds

This adds missing information to the legacy TAU thresholds in the L1Menu

• The information is in a new field "thrValues", so the current menu reader code is not affected
• The existing fields "value" and "isobits" are kept, so the current menu reader code continuous to work
• In the interest of time the reader code will be adjusted later, it should not be needed right now, as here we need to configure L1Calo correctly and they are able to deal with this by reading the json directly. The reader code later will be adjusted such that it can read the old and the updated version of the TAU thresholds

cc @rhowen , @dzanzi