feat(featureflags): improved feature flag handling [EE-4609] (#8222)

* updated and improved feature flags using new module

* merge init into parse

* update the package documentation

* better docs

* minor tidy

api/portainer.go

@@ -9,6 +9,7 @@ import (
 	"github.com/docker/docker/api/types/volume"
 	gittypes "github.com/portainer/portainer/api/git/types"
 	models "github.com/portainer/portainer/api/http/models/kubernetes"
+	"github.com/portainer/portainer/pkg/featureflags"
 	v1 "k8s.io/api/core/v1"
 )
 
@@ -104,7 +105,7 @@ type (
 		AdminPasswordFile         *string
 		Assets                    *string
 		Data                      *string
-		FeatureFlags              *[]Pair
+		FeatureFlags              *[]string
 		DemoEnvironment           *bool
 		EnableEdgeComputeFeatures *bool
 		EndpointURL               *string
@@ -1531,8 +1532,11 @@ const (
 	WebSocketKeepAlive = 1 * time.Hour
 )
 
-// List of supported features
-var SupportedFeatureFlags = []Feature{}
+// SupportFeatureFlags is a list of supported features. They should all be lower case
+// e.g. "microk8s","kaas"
+var SupportedFeatureFlags = []featureflags.Feature{
+	"microk8s",
+}
 
 const (
 	_ AuthenticationMethod = iota