Add ldb RocksDB query tool to the Dockerfile

[teor2345]

Motivation

This adds the ldb RocksDB tool to support expert users querying scanner databases in Docker images. It's also useful for diagnosing chain state database issues in Docker images.

Close #8051.
Initial framework for #8046.

PR Author Checklist

Check before marking the PR as ready for review:

• Will the PR name make sense to users?
• Does the PR have a priority label?
• Have you added or updated tests?
• Is the documentation up to date?

For significant changes:

• Is there a summary in the CHANGELOG?
• Can these changes be split into multiple PRs?

If a checkbox isn't relevant to the PR, mark it as done.

I expect we'll deal with the changelog in the docs ticket #8046.

Debian Package File List

https://packages.debian.org/bullseye/amd64/rocksdb-tools/filelist

Complex Code or Requirements

This adds around 30 MB to the size of the Docker image. But it's already around 1 GB, so that doesn't matter much.

Solution

• Add the RocksDB tools to the test, experimental, and non-experimental production Docker images
• Add a rough framework for a scanner doc, and link to it from other docs
• Add an install doc for the ldb tool

Testing

This image is built in every Rust PR.

Review

This is a routine change.

Reviewer Checklist

Check before approving the PR:

• Does the PR scope match the ticket?
• Are there enough tests to make sure it works? Do the tests cover the PR motivation?
• Are all the PR blockers dealt with?
  PR blockers can be dealt with in new tickets or PRs.

And check the PR Author checklist is complete.

Follow Up Work

• Document how to run and query the results of the blockchain scanning MVP #8046

[arya2]

Looks good!