[META] Condition compatibility with Core/CTools conditions

Meta for tracking compatibility related issues and discussing compatibility related tasks/issues.

Known issues:
#2648276: Fatal errors when core conditions are used
#2609510: Rules 8 immediately WSODed my D8 site
#2675698: Ensure compatibility with core block UI

Plan:
- Modules using core condition API should be fine with conditions written for Rules. They just have lots of context, what might make them not always configurable. But that's regular context API context handling then and will work however the core/CTools/module context handling is implemented.
- Rules needs to deal with condition configuration in addition to the regular context configuration of conditions. We need to do the following: (issues to be created)
-- Import/export/store core configuration values besides the regular condition plugin context config
-- Add / embed the configuration form of core conditions in the Rules UI