Deprecate `crates.parity.io`

[kianenigma]

Broken Link

crates.parity.io

Expected Location

https://paritytech.github.io/substrate/master/sc_service/index.html

Context and Origin

it is not being updated anymore, kill it or auto-forward it.

[TriplEight]

there was an old plan to publish some stuff there, AFAIRC because of the documentation. But if we're ready to publish something to crates.io, usually the doc goes straight there

Agree with @kianenigma , but we should place a redirection to https://paritytech.github.io as it's not obvious from the link that the target is substrate.