CI: Skip CircleCI when no workflow argument is set

[zmarkan]

Closes #

What I did

Create a new CircleCI pipeline param called skipped to skip default workflow run when no external parameters are set (merged, normal, or schedule)

How to test

Commit and push - no workflow should run by default in CircleCI.

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli/src/sandbox-templates.ts
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]