Code refactoring to initialize all singletons and static objects

Numerous objects and data structures throughout the code are initialized within the parent class, but not in the class initialization methods. This would lead to an infinite loop when trying to call the software >1 in the same execution workflow.

This fix includes:
* Re-init of all global variables in classes where identified
* Refactor of DMDocument.main to support the ability to run the software without encountering System.exit()
* Add slf4j for future logging capabilities

Resolves #801

model-dmdocument/pom.xml

@@ -156,6 +156,16 @@
     </build>
 
     <dependencies>
+		<dependency>
+		    <groupId>org.slf4j</groupId>
+		    <artifactId>slf4j-simple</artifactId>
+		    <version>2.0.13</version>
+		</dependency>
+		<dependency>
+		    <groupId>org.slf4j</groupId>
+		    <artifactId>slf4j-api</artifactId>
+		    <version>2.0.13</version>
+		</dependency>
         <dependency>
             <groupId>org.apache.maven</groupId>
             <artifactId>maven-plugin-api</artifactId>

model-dmdocument/src/main/java/gov/nasa/pds/model/plugin/ClassPropertiesBase.java

@@ -58,6 +58,7 @@ class ClassPropertiesBase extends Object{
 	static boolean isFuseki = false;
 
 	public ClassPropertiesBase () {
+		isFuseki = false;
 		iri = "TBD_iri";
 		identifier = "TBD_identifier";
 		versionId = "TBD_versionId";