chore(dependencies): Autobump korkVersion (spinnaker#395)

refactor(core): Upgrade rosco to Spring Boot 2 (spinnaker#392)

* refactor(core): Upgrade rosco to Spring Boot 2

* chore(build): Update gradle scripts to pass enablePublishing

* chore(build): Bump gradle to 5.4.1

refactor(core): Use a rest controller for status endpoints (spinnaker…

…#388)

* test(core): Update tests to test statusHandler

The status endpoint tests are currently testing AllStatusEndpoint and
InstanceStatusEndpoint which are pass-through classes that will be
removed; update the tests to directly test StatusHandler.

* refactor(core): Use a rest controller for status endpoints

The Endpoint classes that are used to implement the status endpoint
have significantly changed in Spring Boot 2. Instead of creating and
exposing an endpoint, just use a rest controller.

* fix(core): Remove package from componentscan

The prior commit moved everything out of the endpoints package into
other packages, so we should remove it from the component scan.

chore(dependencies): Autobump korkVersion (spinnaker#378)

fix(artifacts): Fix NPE on empty artifact (spinnaker#373) (spinnaker#374

)

If an artifact is empty, we throw an NPE when downloading it
rather than just pass an empty artifact along to the caller.

In general it's not overly useful to have an empty artifact, but
in some cases (ex: a values.yaml file for a Helm bake) it's reasonable
to have no content.

chore(packer): ability to add default packer options via spring config (

spinnaker#372)

feat(aws): ability to lookup sourceAmi via dynamic configs (spinnaker…

…#370)

chore(.gitignore) Update .gitignore (spinnaker#363)

chore(.gitignore): Update .gitignore

chore(dependencies): Autobump spinnaker-dependencies (spinnaker#358)

config(provider/azure): update the packer image base vm size (spinnak…

…er#337) (spinnaker#356)