Customize Scope property for Bean properties as required for Spring & Blueprint

Scope in the current implementation of Beans for the purposes of the Global Configuration tab is simply an unvalidated string. We need to change that to provide some standard values that are valid within the configuration.

Essentially in the Bean's properties, instead of a simple String field, the user will be able to select one of the available scope values from a drop-down list. The contents of the drop-down will vary based on whether it's a Spring configuration or a Blueprint one.