Add missing Volume Based Pricing Configuration.

Add missing volume based price configuration feature.
(new for #1856 )

| Q              | A              | 
| ------------- |:-------------:| 
| Bug fix? | no |
| New feature? | no |
| BC breaks? |	no |
| Deprecations? | no |
| Related RFC	| - |
| License | MIT |
| Doc PR	| no |
Same: `<span class="glyphicon glyphicon-plus"></span>`.