plancontext: use helpers to determine if CUE value is secret/fs/service

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

plancontext/secret.go

@@ -16,6 +16,10 @@ var (
 	)
 )
 
+func IsSecretValue(v *compiler.Value) bool {
+	return v.LookupPath(secretIDPath).Exists()
+}
+
 type Secret struct {
 	id        string
 	plainText string
@@ -55,10 +59,6 @@ func (c *secretContext) New(plaintext string) *Secret {
 	return secret
 }
 
-func (c *secretContext) Contains(v *compiler.Value) bool {
-	return v.LookupPath(secretIDPath).Exists()
-}
-
 func (c *secretContext) FromValue(v *compiler.Value) (*Secret, error) {
 	c.l.RLock()
 	defer c.l.RUnlock()