Update the edit rubric templates to include both a name and label for criteria and options

Update container JS to retrieve both name and label for criteria and options

Update schema to make 'name' optional and 'label' required; the XBlock editor handler assigns UUIDs to criteria and options that don't have names

Assign labels to criteria/options if they do not have any

Update the grade template to display criteria/option labels if they're provided, otherwise use the 'name' field

Update student facing rubric templates to display the label if it's available

Add label field to XML problem definition.

Add label field to assessment

Add label field to the data dump script.

Update the turbo mode template to use option labels

Exclude the "name" key for new criteria and options in the JSON dict sent to the server.
Default new option points to 1 instead of NaN

Add data migration to fill in labels with default values
Merge pull request #503 from edx/will/authoring-label-for-criteria

Authoring: label for criteria