Interactive widget: Create and edit rows

[juliushaertl]

Currently our interactive widget of tables content is quite limited as it only lists rows and allows filtering. To contribute to the interactive widgets feature for 29 it would be good to have:

• A create row button that opens the row creation modal and allows users to add rows without leaving their current context
• A edit row button on each of the rows to be able to edit the data

The existing modal components should be reused, one thing I'm unsure about is if they work independently from the vuex store or if we need to have that setup as well in the reference widget entrypoint.