Feature Toggle Admin Page: Implement backend API for GETting feature toggle state

[mmandrus]

GET /api/featuremgmt/toggles
Returns a list of feature toggles, whether they are enabled, and whether they can be updated via the API
Sample response:

[{
	"toggle": "useCachingService",
	"enabled": false,
	"readOnly": true
}]

Endpointswill be guarded by access control middleware to ensure that only users with appropriate privileges can view and update feature toggles.

For the initial step, we should just return all feature toggles and their state. We can worry about filtering them afterwards.