refactor: dynamic fee support should be generalized to work with Skip Fee Market module

[jtieri]

#1412 added support for querying the dynamic gas price base fee on Osmosis but it is currently hardcoded to only work with the Osmosis EIP-1559 implementation.

Once Skip's Fee Market module is live we should refactor this code so that it is generalized for all chains that may be using the module. This allows us to support many different fee market models on any Cosmos chain.