TEIIDDES-1891: Handle no security settings in WAR creation

* When creating a webservice or rest war, the security credentials can not
  always be set. In which case, property collections return null, causing
  exceptions.

* RestWarDataserviceModel
* WarDataserverModel
 * Avoid trying to assign a null value to properties collections. This
   causes an exception since properties objects are backed by hashmaps.

* RestWarDeploymentInfoDataPage
 * Adds in validate methods for the security realm and role

* RestWarDeploymentInfoPanel
 * Avoids trying to apply a null value to a text widget. This generates an
   exception.

* DefaultWebArchiveBuilderImpl
* RestWebArchiveBuilderImpl
* SecurityCredentials
 * Encapsulates the security credentials in their own object ensuring that
   getters will check the security type has been correctly set
 * Avoids calling properties.getProperty().equals which can generate a
   null pointer exception
 * Makes methods private that do not need any more generous visibility