Add Node.js 14.17.1 (default)

What does this MR do?

Add Node.js 14 LTS to asdf configuration and make it the default.

It specifically adds v14.17.1 which is currently the latest version of Node.js 14.

What are the relevant issue numbers?

gitlab-org/gitlab#294180 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Job definition example
  • CI Templates (to be removed)
  • Vendored CI Templates (also in CE)
  • Ensure that all of the ENV vars supported are propagated to Docker containers upon docker run in job definitions
• Conforms to the code review guidelines
• Security reports checked/validated by reviewer