Add support for registered models for direct deployment

[shreyas-goenka]

Changes

This PR adds support for registered models, matching the same behaviour as TF. This PR also adds test server handles for registered models and UC catalogs, as was necessary for the integration test.

Why

To complete coverage for direct deployment.

Tests

New integration test.

[eng-dev-ecosystem-bot]

Run: 18109060162

	Env	✅​pass	❌​FAIL	🙈​skip
❌​	aws linux	314	4	531
❌​	aws windows	315	4	530
✅​	aws-ucws linux	431		428
✅​	aws-ucws windows	432		427
❌​	azure linux	314	4	530
❌​	azure windows	315	4	529
✅​	azure-ucws linux	431		427
✅​	azure-ucws windows	432		426
❌​	gcp linux	313	4	532
❌​	gcp windows	314	4	531

Test Name	aws linux	aws windows	azure linux	azure windows	gcp linux	gcp windows
TestAccept	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL
TestAccept/bundle/deploy/registered_models/basic	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL
TestAccept/bundle/deploy/registered_models/basic/DATABRICKS_BUNDLE_ENGINE=direct-exp	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL
TestAccept/bundle/deploy/registered_models/basic/DATABRICKS_BUNDLE_ENGINE=terraform	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL	❌​FAIL