Add a --playground flag on op-rbuilder to start with the flags required to run the builder on playground

[karim-agha]

Issue: #9

This change adds the ability to autoconfigure op-rbuilder to run a locally deployed builder-playground.
Follow the instructions on how to start a builder playground under this repo: https://github.com/flashbots/builder-playground

Now we can use the following startup parameters for op-rbuilder:

• ./op-rbuilder node --builder.playground This will start using the default $HOME/.playground/devnet directory
• ./op-rbuilder node --builder.playground=<PATH> Will use the provided path as the working directory of the playground

---

You can also use just run-playground command that will automatically build op-rbuilder with the right features enabled and run it in playground mode.

✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)

[SozinM]

let's just create Makefile (Justfile) command to run it?

[karim-agha]

let's just create Makefile (Justfile) command to run it?

done

[SozinM]

Sorry, wasn't clear enough
My point is that we could do the whole thing with Makefile/Justfile, without rust code
IMO Makefile/Justfile would be easier to extend/maintain/add new cases, esp considering that devops team would be able to do it too (if they would test staff locally)
But i'm not too opinionated about it (only a little bit)

[karim-agha]

Sorry, wasn't clear enough My point is that we could do the whole thing with Makefile/Justfile, without rust code IMO Makefile/Justfile would be easier to extend/maintain/add new cases, esp considering that devops team would be able to do it too (if they would test staff locally) But i'm not too opinionated about it (only a little bit)

No problem. I think that the logic of extracting the playground settings is too complex to be placed in a shell script. No strong opinions either, but if you don't mind I'd keep it now and revisit in a future PR when reintegrating flashblocks.

[ferranbt]

Can you update README on how to use it?

[karim-agha]

Can you update README on how to use it?

done