Move wisski instance code to separate package

internal/component/meta/provision.go

@@ -0,0 +1,14 @@
+package meta
+
+import "github.com/FAU-CDI/wisski-distillery/internal/models"
+
+// Provision provisions new meta storage for this instance.
+// NOTE(twiesing): This is a no-op, because we implement Purge.
+func (meta *Meta) Provision(instance models.Instance, domain string) error {
+	return nil
+}
+
+// Purge purges the storage for the given instance.
+func (meta *Meta) Purge(instance models.Instance, domain string) error {
+	return meta.Storage(instance.Slug).Purge()
+}