Fixes error when trying to create data source in servers view

* CreateDataSourceAction
* CreateDataSourceWizard
 * Queries the connection provider whether the selection from the wizard
   requires a password. However, it is possible for either a model resource
   or a connection profile to be the wizard's selection whilst the other
   object is null. Thus, it cannot be assumed that model resource has been
   selected.
 * Pushes requires password logic into wizard, which sets a flag depending
   on its selection. Flag is stored in the TeiidDataSourceInfo.

* TeiidServerActionProvider
 * Avoids duplicating the 'Create Data Source' action in the context menu