[docs-infra] Improve footer links

Context 🔦

A continuation of https://github.com/mui/material-ui/pull/36556. I would propose these changes.

Steps to reproduce 🕹

Steps:

Open https://mui.com/material-ui/react-switch/#api

Current behavior 😯

Expected behavior 🤔

• 1. I wouldn't expect to see "Careers". As far as we have tried to list job ads from the docs, the conversion rate was pretty bad. By the nature of our business model, people using Material UI are most likely to be on the opposite spectrum of who we need to hire (statistically speaking). Per https://docs.google.com/document/d/1Bj7f6xIufued0R-oxCsViguUoik8MwrDrCrrISWys58/edit where we see too many applications, I think making finding the roles harder is the way to go. #39709
• 2. Not link to LinkedIn. The docs is a space for developers, I think the goal is to make it feel as much as possible a pure open-source vibe, this link creates a commercial license vibe. #39709
• 3. The link to "Store" feels too broad. I think it would be more coherent to reference "Templates" that we have in the side nav.
  More broadly, I think we should push toward killing the noting of "Store". https://webflow.com/templates makes more sense to me, as for X, it should have its own space, and the same goes for our Figma kit.

Ideally, in the future:

• the link to the blog would link to the open-source project-specific blog post, e.g. https://www.hashicorp.com/blog/products/terraform
• the link to the template would link to its own space for the technology used, e.g. https://github.com/mui/mui-private/issues/103

Your environment 🌎

  Don't forget to mention which browser you used.
  Output from `npx @mui/envinfo` goes here.