Delete deprecated board GitHub Actions (#779)

The `new-issues-to-triage-project.yml` Action automatically adds issues to a few different classic GitHub boards that we're no longer using. 

This PR deletes the now-unnecessary action.

Authors:
  - Ben Jarmak (https://github.com/jarmak-nv)

Approvers:
  - H. Thomson Comer (https://github.com/thomcom)
  - AJ Schmidt (https://github.com/ajschmidt8)
  - Mark Harris (https://github.com/harrism)

URL: #779