Add mevboost to the quickstart setup

[g11tech]

Add mevboost to the quickstart setup cc @philknows

now with additional flag: --withMevBoost mevboost will be setup for the beacon node and validator (if validator is also being spawned using --withValidator or independently --justVC)

Will update readme accordingly

[philknows]

This can also be in a new PR if necessary, but is there a way to allow a min-bid arg set with setup.sh we can have so people can easily indicate their min-bid if they use --withMevBoost ? Will help ensure they can produce vanilla blocks if there's no high reward blocks proposed.