feat(cast): add JWT secret configuration

[Rjected]

Motivation

I was trying to use cast as an engine API debug tool for reth, when I realized that ethers-rs does not have easy bearer token generation, and cast rpc did not have JWT secret support.

Solution

Added bearer token generation utilities in gakonst/ethers-rs#2529, which are used in this PR. This PR is dependent on the ethers PR, which is why there are patches.

TODO

• Idea from @gakonst: cast rpc --jwt <file>, which takes in a file, replaying the RPC calls in the file line-by-line. Similar to hurl
• Clarify jwt arg and env variable to make sure the user knows the input should be a hex-encoded JWT secret, not a token
  • should there be an option to use a raw token?
  • allow taking a file as input? for example the jwt.hex that reth outputs.
• Remove patches
• Add usage docs

[Evalir]

hey @Rjected is this mostly g2g? do you want us to take over?

[Rjected]

hey @Rjected is this mostly g2g? do you want us to take over?

yeah I plan to do the following today:

• add some usage docs
• change flag name to jwt-secret

The hurl idea is cool but is probably out of scope for this PR, so once I do the above two this is good to go.
Another thing I probably won't have time for:

• file input

[Evalir]

That's alright, this is already pretty great—we can incrementally improve in future prs!

[Rjected]

@Evalir this is RFR!

[Evalir]

bro cooked with this one

lgtm! just pushed a smol commit to use const-hex, which we already have at the workspace level

(ci failure unrelated, merging when it passes)