Introduce new Start screen with helpful links

[rbosker]

In order to provide users a better getting started experience let's change our start screen to something that gives users helpful links and information.

We can get started with just that right column, let's add the left one at a later point.

Links:
Getting started: https://docs.figmatokens.com/getting-started - later on the Tutorial file
Documentation: https://docs.figmatokens.com
Slack: https://figmatokens.com/slack (redirects to slack invite)

[six7]

This was shipped as part of V123 🎉