credential validation for execution envs to allow only registry credentials to be associated with them, also adding security precautions for authfile and password, also combined token & password into one term to align with Quay, and added handling to account for users not filling in credential data and add a has_inputs function to simplify checking if the host, username, and password are present in the credential

awx/api/serializers.py

@@ -1412,6 +1412,11 @@ class ExecutionEnvironmentSerializer(BaseSerializer):
             res['credential'] = self.reverse('api:credential_detail', kwargs={'pk': obj.credential.pk})
         return res
 
+    def validate_credential(self, value):
+        if value and value.kind != 'registry':
+            raise serializers.ValidationError(_('Only Container Registry credentials can be associated with an Execution Environment'))
+        return value
+
     def validate(self, attrs):
         # prevent changing organization of ee. Unsetting (change to null) is allowed
         if self.instance: