Store Feature for Messages & Interaction Requests

[elbakerino]

The UIStore currently only contains "value data" which is intended to be "changed from code or input at specific positions".

Leading to:

• only the root always includes all values and e.g. validity report
• only the plugins/widgets are able to access validation results & any data created in a plugins

Which is good for performance and ease of atomic-component based development.

But bad for some more advanced processes which are too complex to handle inside a generic widget, e.g. the easiest way to display "further information" in widgets is with a Dialog, which isn't the best UX solution for a lot of those cases.

The store.messages would implement a system where widgets + plugins can communicate more complex informations between each other and may request other things like "on item delete: clear only item or all referenced items?" decisions from the user.

Complex informations could be e.g.:

• error messages of object levels
• error messages of schema-api calls (or any other such plugin error)
• linting warnings
• status about finishing/aborting Stepper widgets

The internal system should support persistent (deletion controlled by creator) and pub/sub (one time consumable events [broadcast and/or target-routed?]) pattern accesses and writes.