Clean up Docker instructions

[HCastano]

Hey! I ended up running into an couple of issues when using the provided Docker command
since it was using a) an old version of the Celestia node and b) not forwarding the port
used by the JSON-RPC API.

I've updated the README accordingly.

---

On a sidenote, what's the difference between port 26657 and 26658. In the docs it says
both are for RPC but I don't see 26657 used anywhere.

Thanks!

[MSevey]

@HCastano thanks for the contribution!

[jcstein]

On a sidenote, what's the difference between port 26657 and 26658. In the docs it says
both are for RPC but I don't see 26657 used anywhere.

26657 is for celestia-app in this setup https://docs.celestia.org/nodes/celestia-app/#ports

[MSevey]

@jcstein are the ports documented anywhere? which port is for which purpose?
Even though it might be duplication, I think it is worthwhile also documenting in this repo why we are using the ports we do.

[jcstein]

@HCastano would you like to add a piece about the different ports used here? you can find the details in celestia docs here and here

thank you for your contribution and please let me know if you need help (or want me to add that bit)

[HCastano]

@jcstein The Celestia docs don't explain the difference between 26657 and 26658 though. Even in the troubleshooting docs the the text body mentions *57 while the table has info for *58 🤷‍♂️

Personally, my attempts to use port *57 for JSON-RPC requests fail, so I image there must be some difference.

[jcstein]

to clarify, the troubleshooting page is for celestia-node

26658 is RPC for celestia-node (JSON-RPC) https://docs.celestia.org/nodes/celestia-node-troubleshooting/#ports

26657 is RPC for celestia-app https://docs.celestia.org/nodes/celestia-app/#ports

[jcstein]

it sounds like a Celestia-wide description of different ports would make sense both in this readme and in celestia docs

[HCastano]

@jcstein gotcha, didn't realize they were for different node types. I've added a column with the node type for each port, let me know what you think

[jcstein]

amazing! thank you again for the PR and contribution @HCastano 😄

[jcstein]

[nashqueue]

Thank you for your contribution! :)