Revert "Refactoring Loader"

This reverts commit a49079e79b53a6814b1d321abbc472ccea32bc3e.

Conflicts:
	owner/src/main/java/org/aeonbits/owner/LoadersManager.java
	owner/src/main/java/org/aeonbits/owner/loaders/AbstractFileBasedLoader.java
	owner/src/main/java/org/aeonbits/owner/loaders/Loader.java
	owner/src/main/java/org/aeonbits/owner/loaders/PropertiesLoader.java
	owner/src/test/java/org/aeonbits/owner/LoaderManagerTest.java