Experimental Feature Core API

The experimental framework provides:

• A registry to know the available features (client/backend)
• Services to know which feateures are enabled and disabled (client/backend)
• A new UI available on the settings section to let the user enable or disable each experimental feature, only visible if the experimetal framework is enabled ("appformer.experimental.features" -> true), this means that each user will be able to determine which experimental features wants to preview.
• VFS storage for the experimetal features settings under the preferences.git repo. Each user will have his own settings there.

As a developer, I want to be able to access & use API that will provide me methods to list available experimental features and enable/disable individual experimental features.
I want my settings for the experimental features to be user-specific.