Feat/restructuring (#422)

* Did restructuring and made repo validation interceptor an optional bean instead as it makes it more clean

* Moved construction of FHIR servlet into a bean for better reuse of others that would like to depend directly on this library

* Disabled default validation enabled

src/main/resources/application.yaml

@@ -89,7 +89,7 @@ hapi:
     #    default_pretty_print: true
     #    default_page_size: 20
     #    delete_expunge_enabled: true
-    #    enable_repository_validating_interceptor: false
+    #    enable_repository_validating_interceptor: true
     #    enable_index_missing_fields: false
     #    enable_index_of_type: true
     #    enable_index_contained_resource: false