Add todos config for multiple partition scan detector

What does this MR do and why?

Adds configuration for the multiple partition scan detector to list todos consisting of fingerprints of queries that scan multiple partitions, both to decrease noise in the generated report, as well as to allow us to prevent adding new queries that scan multiple partitions.

Relates to #428704 (closed)

How to set up and validate locally

1. Check out this MR branch locally

2. Download a set of auto_explain artifacts from a merged result pipeline (example: https://gitlab.com/gitlab-org/gitlab/-/jobs/5490783483/artifacts/browse)

3. Extract the artifacts.zip:

   mkdir ~/Downloads/artifacts_unpacked
   cd ~/Downloads/artifacts_unpacked
   unzip ../artifacts.zip

4. Run scripts/merge-auto-explain-logs:

   env RSPEC_AUTO_EXPLAIN_LOG_PATH=$HOME/Downloads/artifacts_unpacked/auto_explain/auto_explain.ndjson.gz ./scripts/merge-auto-explain-logs

5. Inspect the contents of p_ci_builds_multiple_partition_scans.ndjson.gz or one of the other files for a table configured in query_analyzers.yaml.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #428704 (closed)