[metrics] Renaming of precision recall metric

[SkafteNicki]

What does this PR do?

Fixes #3057
Make naming more consistent between the functional and class based backend and is also consistent with sklearn naming.

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[codecov]

Codecov Report

Merging #3308 into master will increase coverage by 5%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #3308    +/-   ##
=======================================
+ Coverage      86%     90%    +5%     
=======================================
  Files          88      88            
  Lines        8132    8132            
=======================================
+ Hits         6962    7337   +375     
+ Misses       1170     795   -375