#1506 Implement maxIfEmpty and minIfEmpty methods for collections

[JavierGelatti]

Implement maxIfEmpty and minIfEmpty methods for collections, such that:

[1, 3, 2].maxIfEmpty({ 99 })
            =>  Answers 3

[].maxIfEmpty({ 99 })
            =>  Answers 99

["a", "ab", "abc"].maxIfEmpty({ e => e.length() }, { "default" })
            => Answers "abc"

[].maxIfEmpty({ e => e.length() }, { "default" })
            => Answers "default"

(and analogous methods for minIfEmpty)

[fdodino]

Great first day performance!