Add network.local.* attributes to rpc server span

[thompson-tomo]

Fixes #2862

Changes

Adds the network.local.* attributes to the rpc server spans just like as has been done in the http server spans.

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Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• Links to the prototypes or existing instrumentations (when adding or changing conventions)

[trask]

discussed in SIG meeting, unsure whether to add these since all attributes are technically "opt-in"

[lmolkova]

I'd not add them until we have an ask / feedback that proves them to be useful. Adding opt-in attribute in the future is not a breaking change.

Adding them now might send a signal to instrumentation authors to put an actual effort to support them, but over the years we haven't received asks to add them to RPC server spans.

I think we had them on HTTP spans before we started stabilization process, but also they are customized (description on the address is updated to talk about multi-IP hosts), so there might be some scenario behind it there.

[trask]

Closing based on #2876 (comment)