Add UI webviews to support SAML SSO flow

[lukeheath]

Tasks

1

• Add webview page to support SSO login transactions.
• this page is almost invisible to the user except:
• While we do the first request to the Fleet server, we need a loading state here (purple screen around 0:30 in the video)
• When the "initiate SSO" request is completed, we need to redirect the user to the IdP
• If there's an error initiating SSO, or during the SSO callback, we need to be prepared to display an error in this page
• A prototype of this component without error handling can be found here.

2

• Add webview page to show EULA
• We need another page (or the same, using different query params) to show the EULA, this page:
  • Receives an URL to redirect the user when the EULA is accepted
  • Shows the EULA and redirect the user to the provided URL when accepted
  • Include "Agree" button.

Figma

https://www.figma.com/file/hdALBDsrti77QuDNSzLdkx/%F0%9F%9A%A7-Fleet-EE-(dev-ready%2C-scratchpad)?node-id=15444%3A198885&t=1vA2CvE0wK4x3FzN-1

[lukeheath]

Hey team! Please add your planning poker estimate with Zenhub @gillespi314 @roperzh

[lukeheath]

Please add your planning poker estimate with Zenhub @ghernandez345

[noahtalerman]

Hey @ghernandez345 I added the Figma link to wireframes of the webviews to the issue description.

We bought this wireframes to design review today as part of emergency drafting (2023-04-11)

cc @georgekarrv

[fleet-release]

Webviews for SAML flow,
Easier SSO path,
Nature's breeze guides us.