(still needs more work)

Bug: T297991

* Remove version-based directory structure
* Add single, per-tool ci template files, based upon configurable
  docker-registry.wikimedia.org images (via new env var)
* Update ci templates to support multiple, nested package/-lock.json files
* Add support for configurable tool options (via new env var)
* Other misc. cleanup

* Re-work logic for npm audit options variable checks

* Add separate echo statements instead of newlines, which is apparently how this must be done in gitlab ci console output :/
* Add support for WM_APPSEC_NPM_AUDIT_OPTION variable to override default secteam npm audit options

* Try different approach to echo newlines (may not work)
* Add review msg if at least one vulnerable package.json exists

* Remove user commands as those aren't supported here, apparently (https://gitlab.com/gitlab-org/gitlab-runner/-/issues/2750)