Add installation Wizard first page

[kshmidt-digma]

Implement first time installation Wizard first page (backend install and wait for install) #369
https://www.figma.com/file/MTZJH09SSbyJjrKkbXcd3L/UX---shared?node-id=154%3A19759&t=VbH4yyOfhQ8P0J7v-1

This first page will present the user with instructions on how to install Digma.
Optionally, it will include a button with a link to install Digma via an extension.

The view will wait for Digma to become available and then allow the user to proceed to the next screen.

If the user skips/close the idea, there is no way to go back.
We will add a link in the 'No Connection' widget of Digma to go back to this page.