[types][beta-5] fixed stacked scale, changed default type for data.labels (#8001)

* Scale: added the stacked property for all scales
* interfaces: generic type LABEL can be string, Date, etc.
* controllers: stack can be used for all types of dataset
* docs/data-structures: added general dataset properties

Co-authored-by: Sergey Khomushin <sergey@placer.io>