Remove index.jsx from docs and redirect landing to /docs

[Savio-Sou]

Problem

https://noir-lang.org/ current lands on the index.jsx page with boxes for readers to self-categorize their interests and backgrounds:

@noir-lang/developerrelations brought up the self-categorization could hurt DocEx instead of improving it though, leaving readers confused and frustrated as their understanding of the categories might not necessarily match how doc authors comprehend them.

Happy Case

Go agnostic:

1. Remove index.jsx
2. Redirect https://noir-lang.org/ to land on https://noir-lang.org/docs/ (i.e. index.mdx)

Project Impact

Nice-to-have

Impact Context

Improve docs reading experience.

Workaround

Yes

Workaround Description

Promote https://noir-lang.org/docs/ instead of https://noir-lang.org/.

Additional Context

The index.jsx page was introduced in #4081.

Would you like to submit a PR for this Issue?

None

Support Needs

No response