Add a new radio button option to "use existing schema's namespace" when replacing an existing schema

[tviegut]

An additional radio button should be added to the current list shown on the "Import Schema" dialog (see screenshot). The option should allow selection of the existing schema's namespace when importing a new version of the same named schema over an existing option. When this radio button option is selected the existing field should auto-populate with the existing namespace.

This should help solve a commonly observed usability issue when end users working against a base CIM model and are modeling custom extensions and need to re-import schema changes multiple times as their model evolves. Usability-wise this should eliminate an end having to exit in order to copy/paste the namespace into the field which may not match one of the predefined radio button options.

[tviegut]

Completed as below.