Support shadow databases

[eandre]

This adds support for having Encore manage shadow databases, commonly used with database migration tools like Atlas and Prisma.

[encore-cla]

All committers have signed the CLA.

[github-actions]

Test Results

    2 files  +       1  227 suites  +65   7m 0s ⏱️ - 21m 21s
716 tests +   185  713 ✔️ +   195  3 💤 +3  0 ❌  - 4 
716 runs   - 1 863  713 ✔️  - 1 853  3 💤 +3  0 ❌  - 4 

Results for commit c3dd0e4. ± Comparison against base commit 6d9c53c.

This pull request removes 17 and adds 202 tests. Note that renamed tests count towards both.

encr.dev/e2e-tests ‑ TestRun/encore_currentrequest
encr.dev/e2e-tests ‑ TestRun/et_override_user
encr.dev/e2e-tests ‑ TestRun/et_override_user_authdata
encr.dev/e2e-tests ‑ TestRun/experiment_local_secrets_override
encr.dev/e2e-tests ‑ TestRun/fallback_routes
encr.dev/e2e-tests ‑ TestRun/graceful_shutdown
encr.dev/e2e-tests ‑ TestRun/pubsub_method_handler
encr.dev/e2e-tests ‑ TestRun/pubsub_ref
test/svc ‑ TestRun
test/svc ‑ TestRun/encore_currentrequest
…

encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/echo
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/invalid
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/raw
encore.dev/appruntime/apisdk/api ‑ TestDescGeneratesTrace/unauthenticated
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/echo
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/invalid
encore.dev/appruntime/apisdk/api ‑ TestDesc_EndToEnd/unauthenticated
encore.dev/appruntime/apisdk/api ‑ TestRawEndpointOverflow
…

♻️ This comment has been updated with latest results.