Replace components with tailwind

[oubiwann]

Tasks:

• First draft (conversion to tailwind)
  • top navbar
  • search
  • downloads
  • tabbed "Feature" carousel
  • "Features" section
  • "Build it with LFE" section
  • "Books" section
  • "Videos" section
  • remaining sections
  • footer
  • components for content pages

[oubiwann]

Here's the branch:

• https://github.com/lfe/lfe.github.io/tree/tailwind-migration

[oubiwann]

Done.

[oubiwann]

Style fine-tuning is getting done in this ticket:

• Refine Tailwind CSS customisations for site refresh #116