Allow cloning of ReadWriteLogRecord

[pellared]

Follows #4062

Why

1. There is a need to make a deep copy of a ReadWriteRecord in order to implement an experimental isolating processor outside of the SDK (as it is experimental, we prefer to land it to contrib repository first).
2. Allow fine-grained control for the users to make a deep copy only when necessary. This allows users to have more control on the processing e.g. pass a clone to asynchronous processor to avoid race conditions or make performance improvements.

Pre-work

• We already have this in OTel Go Logs: https://pkg.go.dev/go.opentelemetry.io/otel/sdk/log#Record.Clone
• slog (standard library in Go) also offers cloning records: https://pkg.go.dev/log/slog#Record.Clone
• A clone is also in OTel Rust Logs: https://github.com/open-telemetry/opentelemetry-rust/blob/0303a38758dd5822a7fbc809f6623ab69caf02c1/opentelemetry-sdk/src/logs/record.rs#L8

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[carlosalberto]

So IMHO we should merge this, specially after we got @cijothomas's review. A note on why this is added would help? i.e. regarding helping implementing #4062 if applicable.

[pellared]

A note on why this is added would help?

In the PR description or the specification itself?
It is already there in PR description.

[carlosalberto]

In the Spec ;)

[pellared]

@carlosalberto PTAL c898c54