Cleanup PriceList, PriceListType and Interfaces

The patch doesn't introduces any heavy conceptual changes. It's about cleanup, simple fixes of parameter names and adding missing
pieces in the interface and implementation, as well as fixing the doc comments.

- Adds missing conditions base fields
- Adds missing condition getters and setters to price list and interface
- Adds missing start and end date methods
- Adds sort and getDefaultStartDate helper methods
- Adds the available helper method, that checks whether a price list
is enabled and the current date is in the range start date <> end date.
- Adds the weight method to both, the price list type and the interface
- Use enabled / disabled instead of published, as commerce core does in such cases
(like promotions)
- Adding the missing start date and end date methods
- Adding some more labels in price list entity definition
- Makes price lists translatable
- Adds commerce cores access handler to price list type
- Using drupals DefaultHtmlRouteProvider for price list types. No need to provide an own
handler that duplicates the code without any relevant changes.
- Delete PriceListTypeHtmlRouteProvider ^^
- Change the admin permission in price list type to meet commerce core standard
- Let the PriceListTypeDeleteForm extending CommerceBundleEntityDeleteFormBase, because it
prevents deletion if it used somewhere.

ToDo:
- decide whether to remove the bundles (price list types)
- decide whether to remove the stores reference field