Add functions to Collection

[Bl00D4NGEL]

This PR introduces a couple of useful functions to the Collection class.

The introduced functions are:

• fromIterable - enables users of the collection to construction the collection from an iterable value like iterators, generators, etc.
• every - Returns true if given callback returns truthy values for all items
• none - Returns true if given callback returns falsy values for all items
• some - Returns true if given callback returns truthy values on some items
• first - Get the first element of the collection that matches a callback, if given. Throws exception if collection is empty or predicate is never satisfied
• firstOr - Same as first but returns $fallbackValue if collection is empty or predicate is never satisfied
• last - Get the last element of the collection that matches a callback, if given. Throws exception if collection is empty or predicate is never satisfied
• lastOr - Same as last but returns $fallbackValue if collection is empty or predicate is never satisfied
• isEmpty - Returns whether the collection is empty
• hasItems - Returns whether the collection has items