(Refactoring) cbioportal-core and integration tests

[dippindots]

This epic will log issue around cbioportal-core and integration tests:

cbioportal-core

• cbioportal backend project doesn't build on jitpack
• cbioportal backend version outdated (currently on v6.0.3)
• automatically publish docker image to docker hub

integration tests

• cbioportal-docker-compose should use cbioportal-core's docker image instead of using jar file directly
• all integration tests should use pr's new database scheme for testing

More issues coming