Update reference hardware

[ggwpez]

Fixup for #3550

TODOs for moved to #3653:

• Mention Docker (and probably why not to use it)
• Give some price estimations
• Mention benchmark machine command

[shawntabrizi]

do we always need to specify a specific rust nightly date? they cannot just always try latest nightly?

[wpank]

We should say to check the release notes, as the rust versions are pinnned to the release that our clean room machine builds our binaries with that successfully work

[bakhtin]

I updated the Rust compiler recommendations and suggested to check out the release notes for the exact version if one runs into the compilation errors.

[dvdplm]

I think we use new Rust features almost as quickly as they come out so I think it's probably better to do what Shawn is suggesting: go with the latest nightly.

[ggwpez]

I put in in here #3653

[wpank]

I would also add a short section on how to run and interpret the ./polkadot benchmark machine command, so that people can compare their machines with the reference hardware. Besides that, this looks good to me.

[wpank]

We should say to check the release notes, as the rust versions are pinnned to the release that our clean room machine builds our binaries with that successfully work

[ggwpez]

@DrW3RK should be ready for a review now. Please let us know what you think.

[DrW3RK]

Some minor fixes and suggestions. Hopefully, they did not change the context or mess with the intended ideas.

[bakhtin]

@DrW3RK I addressed all of your comments.
Can someone, please, approve running a workflow for the PR as GH restricts running it for the first-time contributors?

[DrW3RK]

The validator docs are live now https://guide.kusama.network/docs/maintain-guides-how-to-validate-kusama
https://wiki.polkadot.network/docs/maintain-guides-how-to-validate-polkadot