This:
1. Updates the builtin actors bundle (for actors v10).
2. Updates the event entry type to include the codec.
3. Removes the cbor encoding and zero trimming from event data.
I've chose to:
1. _Not_ add codec handling to the event filtering system for now.
2. _Skip_ events with unexpected codecs.
We don't actually _allow_ these events in the FVM right now, and it
simplifies the implementation.
However, I _am_ recording the codecs in the database so we don't have to
migrate it later.
- Event keys are now t1, t2, t3, t4 for topics; and d for data.
- ref-fvm no longer stores events in the blockstore for us. It just
returns events to the client, who is now responsible for handling
them as it wishes / according to its configuration.
- Add a flag to VMOpts to have the events AMT be written in the blockstore.
- Add a flag to the ChainStore to advertise to the rest of the system
if the ChainStore is storing events.
- Enable that flag if the EthRPC is enabled (can also add an explicit
configuration flag if wanted).
