REST implementation of a couple of GET functions

Code coverage is sitting at 81.1%

Important:

• Java 8 features used: Stream (just marginally), and Optionals

The project has exactly what it needs to function, and was made in a bit of a hurry.

From a quick look, here's what could be improved:

• Defining more test cases (code coverage was OK, but testing all possible scenarios was not)
• Detailed Javadocs
• Moving the .gitignore file to the project's root, and ensuring it's properly configured
• Endpoint implementation of the remaining CRUD Operations on both City and Country entities
• Proper integration testing in a different build phase
• Mock providers for data reusability among tests

Thank you!, Marcel