fix: remove state from executors context and deduplicate entries

[pmelab]

Package(s) involved

@amazeelabs/executors

Description of changes

Simplify @amazeelabs/executors:

• Remove the state
• De-Duplicate executors

Motivation and context

To make sure executors can be live-updated (e.g. for previews).

How has this been tested?

• Unit tests