CI: test and update ci image, codeowners (#8142)

* CI: prep for the new ff deployment

* CI: variable for CI image

* git: add CI team and remove Max from CODEOWNERS

* CI: diener should be updated in CI image, not here.

* CI: diener should be updated in CI image, not here.

* CI: run cargo deny on changes to manifests and lock; run build jobs on schedules [skip ci]

* CI: remove flaming-fir deployment, it will be handled from s3 updates [skip ci]

* CI: trigger simnet with a certain substrate version

* CI: remove cargo-audit in favor of cargo-deny; prepare for being triggered

* CI: prepare to be triggered

* CI: chore