feat: Improve pointers to currently available waku services

[chair28980]

Dedicated section on the landing page for "What you can do with Waku", summarizing what users can start doing immediately with Waku tech.

Point directly to current libraries, SDKs, and tools available in the docs. A "start building with Waku" button that leads directly to the docs.

Example: https://xmtp.org/

Tagline ideas:

• "Waku is a protocol and a network". -- We might not be ready from a marketing standpoint to go live with this language.
• "What you can do with Waku immediately..."

[chair28980]

@hackyguru is there content we can cherry-pick from your live presentation to include in the landing page to address this point?