Use of internal/pubsub in examples folder

[containerman17]

Here is a list of packages currently used in the example VMs. The issue is that internal packages cannot be accessed outside of the repository due to compiler restrictions.

• github.com/ava-labs/hypersdk/internal/state/tstate
• github.com/ava-labs/hypersdk/internal/keys
• github.com/ava-labs/hypersdk/internal/pubsub

To resolve this, we either need to move these packages out of the internal folder or extract their functionality or interfaces elsewhere. Moving the packages seems like the simplest solution.