Implement new landing page

[visortelle]

The goal is to implement a new landing page for the Apache Pulsar website.

https://www.figma.com/file/0jERoA2DTlfQoj1uH09FxQ/Pulsar-website?node-id=368-659&t=jzmCvMLZsIiV0cP6-0

• Work on separate branch pip-249
• Get rid of Tailwind.
• Set font src/css/custom.css using --ifm-font-family-base https://github.com/tealtools/pulsar-site-pip-249/blob/a23394c9a5e2bc24a5cc73127bacb72e6424c9fc/src/css/custom.css#L57

I believe we can get rid of 99% of the custom.css file content, but don't touch it too much now.

• Create a new src/components/HomePage directory, HomePage.tsx, and HomePage.module.css.

All screens should be in nested directories like src/components/HomePage/PulsarFeatures/PulsarFeatures.tsx

• Implement the desktop version of the page.

A mobile mockup is coming soon, don't worry about it for now.

• All reusable components like buttons, header, footer, and cards put to the src/components/shared directory.

Tips:

• Use Figma SVG export to export illustrations.
• You can hide Docusaurus header and footer for now https://github.com/tealtools/pulsar-site-pip-249/blob/a23394c9a5e2bc24a5cc73127bacb72e6424c9fc/docusaurus.config.js#L275

Implement them as separate React components. Then we'll integrate it with Docusaurus.