Technical blueprint for frontend access to KAS

Scope

This issue is part of a bigger development effort described in detail by its epic. The scope of this issue is to come up with a technical blueprint for the epic.

Actions

• Technical proposal. We have a design doc MR that talks about authn with cookies but we don't have technical design on when and what sets the cookie. This needs to be added to the linked doc as part of this issue.
• Iteration plan with rough work estimates.