Make configuration values adjustable via governance

[sea212]

Currently many of the configuration values of the prediction market protocol (including surrounding pallets like swaps) can only be changed via a runtime upgrade. For example, the governance body cannot currently decide how much ZTG is required to be bound for creating markets, specifying oracles, adding disputes etc. However, the value of the same amount of ZTG changes over the course of time. It should be determined which configuration values shall be adjustable by the governance body and what possible side effects can occur by changing those.