support SPA dev

[pdurbin]

What this PR does / why we need it:

We want a developer to be able to spin up the backend in this repo and then make use of that running environment while doing frontend development.

Here's a good entry point for doc changes: https://dataverse-guide--12746.org.readthedocs.build/en/12746/developers/dev-environment.html#quickstart

Which issue(s) this PR closes:

None. Related:

• fast redeploy of full stack (backend and frontend) dataverse-frontend#689

Special notes for your reviewer:

The bulk of what's going on in this PR is setting up Keycloak enough for the SPA to use it.

Suggestions on how to test this:

• In this repo, run mvn -Pct clean package docker:run
• In the frontend repo, run npm start -- --host. See docs on how to work with backend dev env dataverse-frontend#1089
• Go to http://localhost:8000/modern and log in with dataverseAdmin/admin1
• To test file upload from the SPA, change a collection's storage to "S3". (This must be done in JSF or API until Add StorageDriver select component to CollectionForm.tsx dataverse-frontend#997 is merged.)

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

Is there a release notes update needed for this change?:

Additional documentation:

[github-actions]

Test Results

408 tests  +1   394 ✅ +2   32m 3s ⏱️ +9s
 55 suites ±0    14 💤  - 1 
 55 files   ±0     0 ❌ ±0 

Results for commit 4c2f35a. ± Comparison against base commit cdcb7f7.

♻️ This comment has been updated with latest results.

[coveralls]

coverage: 25.556% (+0.006%) from 25.55% — spa-dev into develop

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

📦 Pushed preview images as

ghcr.io/gdcc/dataverse:spa-dev

ghcr.io/gdcc/configbaker:spa-dev

🚢 See on GHCR. Use by referencing with full name as printed above, mind the registry name.

[poikilotherm]

I am approving this under protest. It should work, shouldn't break anything and will unblock people interested in using the SPA in dev.

That said, the whole Keycloak thing is huge pile of technical debt and of dubious quality. It will mess with the Dataverse database. Don't try this at home or in your production environment. We (I) are fixing things at https://github.com/gdcc/keycloak-dataverse-extension as part #12597