Skip Tests on Draft and WIP Pull Requests

[mrmundt]

Fixes NA

Summary/Motivation:

We have been getting a lot of Draft and WIP requests lately, and they are cluttering up the CI build queue. We are changing the policy to enforce and tools.

Changes proposed in this PR:

• Do not run tests on draft PRs and PRs that start with [WIP]
• Add information to the contributor's guide
• BONUS: If a test suite is cancelled, don't trigger the code coverage jobs

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.39%. Comparing base (f15a1da) to head (00041ff).
Report is 72 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3223      +/-   ##
==========================================
- Coverage   88.39%   88.39%   -0.01%     
==========================================
  Files         847      847              
  Lines       95272    95272              
==========================================
- Hits        84217    84213       -4     
- Misses      11055    11059       +4     

Flag	Coverage Δ
linux	86.33% <ø> (ø)
osx	76.18% <ø> (ø)
other	86.53% <ø> (ø)
win	83.82% <ø> (ø)

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[blnicho]

One minor rewording suggestion but otherwise this looks good.