Implement: Authentication and authorization for Blazor

[danroth27]

Scope

This will be something similar to what the SPA templates have in terms of functionality.

We will try to simplify the amount of code and put it in libraries so it can be serviced.

Things to consider:

• Login/registration/etc systems, 2FA, etc. - probably delegate to existing identity UI if at all
• Simpler cookie-based auth system
• Authorization on a per-component basis
  • Ability to control the auth logic
  • Ability to tie in with server-side (MVC) auth policies

Design notes: https://gist.github.com/SteveSandersonMS/60ca3a5f70a7f42fba14981add7e7f79

[danroth27]

Some thoughts from the community here: https://brockallen.com/2019/01/11/using-oauth-and-oidc-with-blazor/