[website] Adapt website and README for Apache top-level project

[michaelkoepf]

Purpose

Linked issue: close #3763

• Removed all "Incubating" disclaimers
• Adapt release and verification instructions to Apache TLP
• Adapted roles to Apache TLP (PPMC -> PMC)
• Updated team list

Out of scope: Updating glue.md and hive.md. They have hardcoded Fluss versions (0.9.1-incubating`). To be updated with a separate PR for the 1.0 release.

[michaelkoepf]

removed the agains the KEYS file as it is redundant. It is mentioned in the verification instructions.

[wuchong]

Thanks @michaelkoepf , this PR looks good to me. I also copied the KEYS file to TLP relealse svn to make the link https://downloads.apache.org/fluss/KEYS available.

IIUC, this PR only focus on the website changes, and other changes (like source code) should be handled by other PRs, such as I found #3750 handles source code changes.

I will merge this and continue the source code change review in #3750.

[wuchong]

One open question: fluss-rust/website and fluss-rust/docs appear to overlap with the client documentation now under website/*, but clients.fluss.apache.org is still live and .github/workflows/rust-docs-check.yml still builds the standalone site. If that site is being retired, we should remove the directory and workflow together and arrange a redirect. Otherwise, we should keep it and update its incubation-related content. cc @luoyuxia @fresh-borzoni what do you think?

[fresh-borzoni]

@wuchong Good question 👍
I think we need to ask INFRA to move clients.fluss.apache.org off GitHub Pages onto the Fluss vhost. I'll handle this week and then we can archive fluss-rust repo.
Before this I'll strip incubation related content to match graduation.