CMake install find_dependency(), add changelog, refactor, etc

[victor1234]

• Add find_dependency() for metric cmake package
• Add cmake variables for tests, benchmarks and examples
• Move metric.hpp to metric/
• Add changelog
• Update and fix readme
• Update and fix CI

[codecov-commenter]

Codecov Report

Merging #319 (41cf969) into master (625febe) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 41cf969 differs from pull request most recent head 0c362d8. Consider uploading reports for the commit 0c362d8 to get more accurate results

@@           Coverage Diff           @@
##           master     #319   +/-   ##
=======================================
  Coverage   86.79%   86.79%           
=======================================
  Files          49       49           
  Lines        4150     4150           
=======================================
  Hits         3602     3602           
  Misses        548      548           

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 625febe...0c362d8. Read the comment docs.