Add CMake modules for finding and and executing Fusion

[msteinbeck]

Note that the CMake modules are licensed under the same terms as those modules shipped with CMake (the BSD 3-Clause License). I know that Fusion is licensed under the terms of the GPLv3 license, but I'm not sure what the implications are if these modules are included in other projects.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.39%. Comparing base (850a29f) to head (65c2db5).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #206   +/-   ##
=======================================
  Coverage   96.39%   96.39%           
=======================================
  Files           2        2           
  Lines       18430    18430           
=======================================
  Hits        17766    17766           
  Misses        546      546           
  Partials      118      118           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.