Run dual tests for Synthetix

op-exporter version nil deference

integration-tests: Actor updates to run against nightly

- Modifies the existing actor tests to use predeployed contract addresses
- Exposes metrics about the actor via Prometheus

To see how the actors are set up using Stackman, see https://github.com/ethereum-optimism/stacks/blob/master/nightly/actors.yml.

Fixes ENG-1667

Remove logic for connecting contracts

Fixes codechecks reports

Fix in the generation of the artifacts & doc update

Fail CI if coverage threshold checks fail

fix (generate-artifacts): Unicode fix for the output files  = '\' replaced with '/' because \u is considered a symbol & build throws an error

Docs generation for the Contracts + GH action for detecting missing Natspec comments.  

Increase branch coverage 

ci: Fix merge bug in CircleCI YAML

I encountered merge conflicts in the CircleCI YAML, and missed a stanza that builds proxyd.

ci: Add Slack notifications to nightly deployment

fix: message relayer docker build

maintenance: remove eslint-plugin-ban dependency