Add Collectable.bitAnd(), bitOr() including mapping overloads

[lukaseder]

New methods are:

Optional<T> bitAnd();
<U> Optional<U> bitAnd(Function<? super T, ? extends U> function);
int bitAndInt(ToIntFunction<? super T> function);
long bitAndLong(ToLongFunction<? super T> function);

Optional<T> bitOr();
<U> Optional<U> bitOr(Function<? super T, ? extends U> function);
int bitOrInt(ToIntFunction<? super T> function);
long bitOrLong(ToLongFunction<? super T> function);

Reference type overloads need to return Optional<?>, because the type of the identity value (e.g. Byte, Short, Integer, Long) is not known. Unlike for primitive types, where the identity value for AND is Integer.MAX_VALUE or Long.MAX_VALUE, whereas the identity value for OR is 0