New default login method for Jetstream2 hosted site

Allows for configuration of OpenID Connect as the default login method, to support Jetstream2.

Also, throughout the codebase, I renamed Jetstream to Jetstream1 where appropriate, to avoid confusion with Jetstream2.

Fixes #650 (closed).

How to Test

• Clear your local storage for https://try-dev.exosphere.app (or log out of all projects there), then browse there in a new tab
• You should see a button to to the OpenID Connect login by default

Screenshots

QA Checklist

• Any changes to 'widgets' in src/Style/Widgets/? If so:
  • Update src/Style/StyleGuide.elm showing example usage of that widget
• Were any app flags created, modified, or removed? If so:
  • Update config.js and all files in environment-configs/, including docker-config.js
  • Update "Runtime configuration options" documentation in README.md

Post-Merge Checklist

• Create follow-up issues for anything left over for another merge request
  • If any technical debt is introduced, assign these follow-up issues to the MR submitter