feat: bundle sponsorship

[bertmiller]

Some transactions fail because they lack funds, but they generate mev and are actually profitable to execute if they did have funds to do so. We could "sponsor" them as a builder by transferring some eth to the account that lacks funds before its transaction is executed.

[quasarwin]

We've got a working implementation in our builder for sponsorships. We actually do a precheck during order commit rather than waiting for sim faliure and then retrying.

We're running a fork of rbuilder, but I could probably patch in our changes to the current develop branch on a new branch. Not sure what your process is for testing after that.

[sukoneck]

@quasarwin that would be awesome! No concerns with precheck. Please do raise a PR with your changes and we'll be happy to support your work ⚡

[quasarwin]

Just submitted a PR (#675). It's hard coded to limit to 2 ETH sponsorships. You might want to change that to a configuration, along with an "allow sponsorship" configuration, but I didn't want to add config changes with this PR as well.