Universal helpers for all iterable data structures

[KiraLT]

Instead of having different functions for each data structure (e. g. mapArray, mapRecord, asyncMap...), it would be helpful to have one function which could support all iterable data structures (in short, just one map).

Most data structures have Symbol.iterator, but maybe it is a good idea to avoid using it to increase browser support.

Following iterables should be supported:

• String
• Array
• Simple object
• Map
• Set
• Iterator
• Async Iterator

Suggested iterable functions:

• map
• filter
• flatMap
• reduce
• indexBy
• toArray

Suggested additional helpers:

• isIterator
• isAsyncIterator
• toIterator
• toAsyncIterator