As part of preparation for ESM and node/TSC updates, this PR will make
Unleash build with strictNullChecks set to true, since that's what's in
our tsconfig file. Hence, this PR also removes the `--strictNullChecks
false` flag in our compile tasks in package.json.
TL;DR - Clean up your code rather than turning off compiler security
features :)
## About the changes
Removes the deprecated state endpoint, state-service (despite the
service itself not having been marked as deprecated), and the file
import in server-impl. Leaves a TODO in place of where file import was
as traces for a replacement file import based on the new import/export
functionality
I've tried to use/add the audit info to all events I could see/find.
This makes this PR necessarily huge, because we do store quite a few
events.
I realise it might not be complete yet, but tests
run green, and I think we now have a pattern to follow for other events.
### What
Adds `createdByUserId` to all events exposed by unleash. In addition
this PR updates all tests and usages of the methods in this codebase to
include the required number.
