Build in debug mode for PRs

[timsaucer]

This PR is to improve our CI performance in a couple of ways

• For PRs we can build in debug mode instead of release mode. For RC tags and pushes to main we still run in release mode.
• This gives better debug if there are failures in CI and faster builds.
• We will still catch any errors generated in release mode when the merge to main occurs.
• At the same time, doing some minor cleanup of jobs that may no longer be necessary.