[Feature] ability to generate validator transactions offline

[ibhagwan]

Hi Jim and ty for yet another wonderful project :)

I’m wondering if it would be possible to generate offline tx data for validator commands (especially compound/consolidate/topup) offline and then send the signed tx, similar to what’s done in ethdo validator BLS withdrawal address upgrade to a 0x1 address?

[canbal99]

And I would like to add offline "partial withdrawal" request here :) I hope they will come all together when it's possible.

[ibhagwan]

FYI, I just published my new project eth-knife-rs, it has support for offline transactions as well as validator operations (compound, consolidate, withdrawal and deposit).

@canbal99, would love to get your feedback, I tested it thoroughly on hoodi, nonetheless be extra careful when using it.