LaunchConfiguration can be edited, but will be lost because of deferred delete

The Forge LaunchConfiguration can be changed to allow source lookup.
Due to the fact that the name of the launch config is artificial, it will be destroyed.

By defining a name for LauchConfiguration in the ForgePreferences we can allow for persistent configurations:

• a (list of) names can be defined in ForgePreferences
• each LaunchConfiguration will be associated with a specific Runtime
• Forge development can be assisted by integrating Forge core/dist/target as Runtime
• development of plugins can be assisted be integration of other project's source