feat: introduce the Noop WAL provider for datanode

[WenyXu]

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close #7100

What's changed and what's your intention?

This PR introduces a Noop WAL provider for the datanode. It is designed for situations where the configured WAL provider becomes temporarily unavailable.

In a GreptimeDB cluster, there are two places where the WAL provider should be configured:

• Metasrv — responsible for generating WAL provider metadata for new regions.
• Datanode — responsible for reading and writing WAL data.

This means that when the WAL provider is temporarily unavailable, users only need to configure the datanode’s WAL provider as Noop to keep the cluster functional.

PR Checklist

Please convert it to a draft if some of the following conditions are not met.

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.
• API changes are backward compatible.
• Schema or data changes are backward compatible.