chore(security) #28388 : XML External Entity (XXE) Injection in JDOM

Removes the use of the JDOM library altogether.
The classes using the JDOM library living under the dotCMS/src/main/java/org/apache/velocity/anakia/ and dotcms-integration/src/test/java/com/ettrema/ packages were removed altogether as well.
As per Steve Bolton's suggestion, we're now using the JAXB library to handle XML data representing Portlets in dotCMS. This includes both the Portlets defined in the /WEB-INF/portlet.xml and /WEB-INF/portlet-ext.xml files, and the database.
Additional Javadoc and code refactoring was done.
The dotcms-postman/src/main/resources/postman/PortletResource.json Postman suite was refactored to use JWT, organized into folders, and reviewed t make sure that the REST Endpoint is tested as much as possible.

This PR fixes: #28388

dotCMS / core