Request - Dictionary should have `displayName` separate from `name`

[joneubank]

Summary of request

Every other level (schema/field) has separate property to identify it vs a display value. This should be adopted at the dictionary level as well.

Details

The dictionary name currently accepts any string value, while all other names require no dots or spaces. As a result, no display name was added since you can use the display name as the dictionary name. This means the dictionary.name property has to do double work as a unique identifier for the dictionary that is used programatically to identify the dictionary, as well as the display text for dictionary viewer or other communications. We want to separate the unique name from the display name:

• Add displayName property to the dictionary schema. This should allow any non-empty string, and is optional.

It would be ideal if the dictionary.name property had the same validation rules as other name fields, specifically not spaces or dot characters, but this would be a breaking change to existing data. This would require a major version release of Lectern.

For this ticket, we do not want to modify the validation for the existing dictionary name field.