Login page should act as a landing page

[kisamoto]

In the beginning we'll launch without any marketing or landing pages, just the Cognos app.

To explain a bit more to users about what Cognos actually is turn the login page into a kind of marketing landing page.

Currently visualise it like this:

• Layout
  • [Desktop] Split the screen in half, log in on the right and marketing info on the left
  • [Mobile] tbc
• Explain that Cognos encrypts your AI chats
• Pricing
• Link that opens a modal to describe in depth how the encryption/security works

[kisamoto]

Seeing as we have a basic version with #78 just close this for now