OPENDJ-1963 Use backend type printable name in UI

* src/main/java/org/opends/quicksetup/UserData.java
** Use backend configuration class instead of string to identify the backend selected by user

* src/main/java/org/opends/quicksetup/installer/Installer.java
* src/main/java/org/opends/quicksetup/util/Utils.java
**  Consequences of changes in UserData

* src/main/java/org/opends/quicksetup/installer/ui/DataOptionsPanel.java
**  Consequences of changes in UserData
**  Use BackendTypeUIAdaptors to have user friendly names in combo box

* src/main/java/org/opends/server/tools/BackendTypeHelper.java
**  Create a new satic class which is an adapter of a backend class to allow user friendly printable name in combo box.

* src/main/java/org/opends/server/tools/InstallDSArgumentParser.java
**  Consequences of changes in UserData

* src/main/java/org/opends/server/tools/InstallDS.java
**  Use backend configuration class instead of string to identify the backend selected by user