ISSUE-18725: Investigate set up redirections for javadoc

[sijie]

Original Issue: apache#18725

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@dave2wave wrote:

One more item should be added to this list.

Old api links like p.a.o/api/client/org/… should rewrite to the current main version like p.a.o/api/client/2.10.x/org/…

What do you think? It may be tricky to write.

Here are two questions:

About the motivation: Are there any real-world links to the unversioned pages? As long as we have only versioned links in the doc site, it's a debt to maintain such 'compatibility'.

About the implementation:

We can use either client-side redirections or server-side redirections. Client-side redirections seem like apache/pulsar-site#288, but server-side redirections should be better facebook/docusaurus#7087 (comment).

@dave2wave Do you know how to do server-side redirections with Apache Web Server for such requirements well?