Add a check for base gas fee before interacting with ZetaCore

[lumtis]

Somewhat related to #4237 but for a different parameter

If the base gas fee reach a level too high, the ZetaClient should stop sending messages to ZetaCore as the hotkey wallet might be drained too rapidly.

This should be defined as a non mandatory option. In the ZetaClient config, a value in GWei can define the base gas fee for interactions

[ws4charlie]

The logic is included in 4291