Add Minimal Implementation of MEV-Share SSE Collector

[grayleonard]

Thought I'd get the ball rolling on this. Currently only added a collector following https://docs.flashbots.net/flashbots-mev-share/searchers/event-stream.

I imagine eventually the MEV-Share implementation will have a complementary executor with shared types, so anyone reading feel free to steal this for yourself if doing that.

Added a test as well but wasn't sure what it should test against, any ideas? Also, because MEV-Share has to send out an event before test completes, the test takes an indeterminate amount of time, sometimes ~5s waiting for a streamed event.

Related #4

[FrankieIsLost]

thanks for your contribution! @mattsse's mev-share client looks good, let's please use that inside the collector instead of rolling our own 🙏

[grayleonard]

thanks for your contribution! @mattsse's mev-share client looks good, let's please use that inside the collector instead of rolling our own 🙏

Just pushed commit to use @mattsse's mev-share-rs instead 🙂. It works well.