Prepare RocksDB 9.7.4 release for Debian unstable

Similar to mariadb-team/mariadb-server!97 (merged), this Merge Request contains the import of a new upstream version of MariaDB.

I am requesting review of this before I proceed with upload. The reviewer does not have to be a RocksDB or Debian expert. I am happy with any level of review, as one extra pair of eyeballs is always better than me proceeding with uploading this on my own.

The import was done using gbp import-orig --uscan as explained in the README.source.md. In the image below you can see the debian/latest branch as the target, the upstream/latest branch as the import target, and the branch 9.7fb which is the real upstream git branch that this release came from. This shows the full "supply chain" of what was imported and a diff between each branch will show if they had any differences.

NOTE: There is no need to review merge commits or upstream commits. Just focus on the ones that are made specifically in preparation for this Debian package update to ensure it is done well:

git log --first-parent --reverse --format='format:* %C(yellow)%h%C(reset) %s' origin/debian/latest...

• 5041e833 Update upstream source from tag 'upstream/9.7.4'
• cc9d0814 Update changelog and refresh patches after 9.7.4 import
• b595c112 Update librocksdb9.7 library name to match latest RocksDB version
• 83cafc04 Add myself as uploader and co-maintainer
• 1aaa6f19 Add upstream/metadata file

The additional 651cef1a commit will be removed from this MR before merge. It is only a temporary addition to run reverse-dependency testing in the CI. In addition to the CI here, I also ran the build on multiple architectures with results visible at https://launchpad.net/~otto/+archive/ubuntu/ppa/+builds?build_text=&build_state=all.

I also compared the Lintian logs, file lists etc of a locally run Debcraft build of a previous upload and this version, and it did not reveal any new changes that would require Debian packaging changes.