Sahara/ModifyNodeGroupTemplate

Summary
Modifying a node group template

Release Note
Currently there is 'node_group_templates_update' function. However that function just return the not_implemented function contained the 501 error("This API operation isn't implemented")

In the backend, 'node_group_templates_update' function should be implement completely as defining some new functions. In the dashboard, Create the new file using 'create.py' and 'copy.py'.

When this is implemented, savanna dashboard will show the 'modify template' butten in 'Actions' part  and it can be modify a node group template.

User stories

 * User want to change some content of template, they will click the 'modify template' button.
 * Savanna dashboard will show the selected value.
 * User can be modify some values they want to change.

Design
There are two picture about backend and web design. Red box will be create or modify.



Implementation

 * Rest API process
 * Implement and add 'node_group_template_update' class of each process
 * Savanna dashboard
 * Add 'update template' button

Code Changes

 * Rest API process
 * /api/v10.py
 * /service/api.py
 * /conductor/api.py
 * /manager.py
 * /db/api.py
 * /sqlalchemy/api.py


 * savanna dashboard
 * /node_group_templates/tables.py
 * /node_group_templates/urls.py
 * /node_group_templates/views.py
 * /api/node_group_templates.py

Test/Demo Plan

 * 1) Using the modify function, change the values what you want.
 * 2) Confirm the values of node group template was changed.

Unresolved issues
TBD