Add ifF on Functor #3040

[vasiliybondarenko]

Added ifF function to Functor:

def ifF[A](fb: F[Boolean])(ifTrue: A, ifFalse: A): F[A] = map(fb)(x => if (x) ifTrue else ifFalse)

[codecov-io]

Codecov Report

Merging #3058 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3058      +/-   ##
==========================================
- Coverage   93.52%   93.51%   -0.02%     
==========================================
  Files         368      368              
  Lines        6998     6999       +1     
  Branches      198      188      -10     
==========================================
  Hits         6545     6545              
- Misses        453      454       +1

Impacted Files	Coverage Δ
core/src/main/scala/cats/Functor.scala	100% <100%> (ø)	⬆️
core/src/main/scala/cats/data/NonEmptyList.scala	98.66% <0%> (-0.67%)	⬇️

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