- Use the DecoderRegistry instead of the container (e.g. to retrieve
other chunks etc)
- This is still a bit fiddly, with multiple responsibilities for the
decoder to also act as chunk provider... might have to revisit this
later.
- Factories can check if there's a decoder with a given strong type
(instead of class name) through the registry
- Views should now call `reload()` on the decoder to decode data.

It's not in its final form yet, but this does get things working based
on the new libdbpf structure itself.