Consider removing base fee reference from transaction pool

[shuse2]

Description

Remove base fee reference from transaction pool.

Motivation

Fee would be one of the modules, and the parameters will should be defined in the module.
Because we currently require those 2 properties, they are part of the genesis config which all module shares.

Additional Information

When this is achieved, we should remove baseFees properties from the genesis config

[shuse2]

The concept of base fee can be removed. Each command will define special fee in params if additional cost is required for the particular command