Enable Fauxton to authenticate to CouchDB with a JWT access token

[Stwissel]

Overview

Preliminary pull request - not ready for merge yet. To collect feedback.

• Added a button: Login with IdP
• Added a form to capture IdP info and store in session store
• Added code to obtain authorization code, access token & refresh token
• Added code to spin up CouchDB & Keycloak containers including documentation
• Added IdP.md to document
• modified ajax.js to add authorization header if token is still valid
• added code to use refresh token to obtain new access token

Testing recommendations

• Follow the steps in idp.md.
• There's a shell script (macOS/Linux only) that configures containers to so CouchDB recognizes the Keycloak public key.

Open questions / feedback

• How to optimize user flow? (e.g. let the IdP URL point to .well-known?)
• What should be tested
• should the config dialog be hidden once set?
• should the code changes be less sprinkled over?
• currently the IdP login is its own page, should it be merged and show/hide with login page
• more ipressions/suggestions

GitHub issue number

Fixes #1457

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;
• Update rebar.config.script with the correct tag once a new Fauxton release is made

[Stwissel]

@janl Comments?

[Stwissel]

Closing pending resubmission with less formatting