[RFC] Database CLI tools

[Altahrim]

Idea

Create CLI tools to investigate database issues.
It should be an easy way to get information about the database:

• version/flavour
• important variables (vs. recommended ones?)
• table/index size
• fragmentation
• cluster info
• buffer pool hit-rate/query cache
• indices usage (used/unused)
• see current locks and blocked queries

Why

A lot of our performance issues are related to database performance. It should help admins to troubleshoot issues quicker.

[rodrigocorreiaist]

Hi, I'm working on implementing this as part of a university project and plan to open a draft PR soon. Happy to align with any preferences the maintainers have.