Think about how to return data

[woutermont]

Components can now ask to read or write Quads, but what with other data? Does it make sense to have SemCom components pass other data (since the app can in principle not know which components are loaded and therefore also not on which events with which data types it should listen)?

[woutermont]

Add a mandatory type and optional mime field to the read event. Copy the write, append and response events multiple times, to allow for the following data types: Quad[], string, json (any) and Blobor Readablestream<Uint8array> (look up whatever is best suited for images and PDFs).