Use or drop config GAS_LIMIT

[calina-c]

Pending discussion: I have noticed that the GAS_LIMIT option inside the config was not actually used in gas calculations. I suggest we either work it into the calculation some way, or drop it from the config dict.

Originally posted by @calina-c in https://github.com/oceanprotocol/ocean.py/issues/953#issuecomment-1254710160

[trentmc]

Let's drop it.

(There are good args for this from a pure sw eng perspective, and from an EVM perspective)