[configgrpc] Remove `ServerConfig.ToListener` and `ToListenerContext`?

[mx-psi]

This option is redundant since one can already call ServerConfig.NetAddr.Listen instead. Should we deprecate it?

[bogdandrutu]

+1, agree.

[bogdandrutu]

Also, as a general rule all these "ToFoo" should have options in the signature for future proof and very important Context as first argument.

[mx-psi]

Also, as a general rule all these "ToFoo" should have options in the signature for future proof and very important Context as first argument.

Split off at #9490