maintainers.md (remove duplication, add council)

[vuvova]

This pull request restructures and clarifies the documentation around maintainers, subsystems, and governance processes for the MariaDB Server project. The main improvements include moving subsystem and maintainer lists to a dedicated file, enhancing the organization of the maintainers.md file, and updating the README.md to reflect these changes and clarify decision-making processes.

Key changes:

Documentation structure and clarity:

• The list of stewards, subsystems, and maintainers has been moved from maintainers.md to a new dedicated file at lists/maintainers.md, improving maintainability and clarity. The main maintainers.md file now links to this new list and provides instructions on how to interpret it. [1] [2]
• The maintainers.md file has been reorganized to clarify the roles of stewards, the Maintainer Council, and the process for updating the maintainer list, as well as detailing voting and decision-recording procedures.

Content updates and corrections:

• The subsystem and maintainer details in lists/maintainers.md have been updated, including clearer scope definitions, maintainer affiliations, and status for each subsystem. Some maintainer assignments and affiliations were corrected or clarified.

README and process improvements:

• The README.md now lists all governance and policy documents in a more logical order and clarifies the processes for changing the repository, including explicit references to both governance and maintainers' decision-making procedures.

General formatting and consistency:

• Headings and formatting in committers.md and maintainers.md have been standardized for consistency and readability. [1] [2]

These changes collectively improve the transparency, organization, and maintainability of the project's governance documentation.

[vuvova]

@gkodinov , in particular, see what I did with lists/maintainers.md and double-check whether it's ok with your approach. I tried to match your grep pattern

[gkodinov]

LGTM, one question to you below.

[gkodinov]

It should work fine with the verification trigger, that I'm still hoping you'd review (#2). As long as you stay within the bounds of the 2 regular expressions I have there. It's easy to check too: https://github.com/MariaDB/governance/actions/runs/30815060977/job/92624664743.
However, it'd be hard to correlate the extra structure here in any kind of automated parser script.
If that's not a goal, then it's fine by me.

[vuvova]

From what I've seen, you grep for ^ *\* , we can keep these lines strictly for membership lists and add any additional info only in a way that does not match this pattern. Then it'll work. The parser will grep and process the output, everything else is filtered out.