users: new package for internal User and Group types

New types that represent a User or Group for internal representation.
These are meant to be used as intermediate representations between API
or Blueprint user customizations and the final OSBuild stage options.

internal/users/users.go

@@ -0,0 +1,18 @@
+package users
+
+type User struct {
+	Name        string
+	Description *string
+	Password    *string
+	Key         *string
+	Home        *string
+	Shell       *string
+	Groups      []string
+	UID         *int
+	GID         *int
+}
+
+type Group struct {
+	Name string
+	GID  *int
+}