Add lint checks for YAML files and a GitHub workflow to run linting checks.

[kirkrodrigues]

Description

This PR:

• Adds a Taskfile to run yamllint on all YAML files.
  • This Taskfile depends on the utility taskfile from yscope-dev-utils.
• Adds a workflow to run the lint task on every PR and daily at 00:15.
• Fixes any lint violations.

Note that we can further refactor the existing GitHub workflows, but that will be left to another PR.

Validation performed

Validated the new lint workflow passed.