Documentation missing for remote scenarios

[arpitkarnatak]

As resolved in #202, we can have scenario files without needing to clone the repository. Simply have to do scenario:<RELATIVE PATH OF THE SCENARIO IN THE SCENARIO DIRECTORY> instead of cloning (as mentioned on https://github.com/flashbots/contender/blob/main/README.md#scenarios)

contender setup scenario:uniV2.toml (if file path is /scenario/uniV2.toml)
contender setup scenario:precompiles/modexp.toml (if file path is /scenario/precompiles/modexp.toml)

We should change it to something like this

contender setup scenario:stress.toml -r $RPC_URL -p $PRIVATE_KEY
contender spam scenario:stress.toml -r $RPC_URL --tps 10 -d 3 -p $PRIVATE_KEY

[zeroXbrock]

fixed in #233