I rewrote the Bag<T>

[warquys]

I forked MonoGame.Extended for net10. I rewrote certain parts of the code.
One class that I liked a lot and rewrote is Bag.

I noticed that it did not implement a System.Collection interface, and that the class did not correspond to the standard of a collection.
For example the Reset method of the enumerator neither throws nor resets.
That it is possible to index an element at an index greater than Count which (if of a primitive generic type) preserves the values from before a Clear.
I rewrote all of that and added documentation. I forked a specific branch for the Bag class https://github.com/warquys/MonoGame.Extended/tree/Bag, in case that can interest you.

I did not create a pull request because these modifications contain multiple breaking changes.
However, I can modify the current branch code to remove them.

The breaking changes are:

• Enumeration throws if the collection is modified during enumeration
• The collection throws if the index is greater than Count during a modification by index.
• RemoveAt throws if the index is greater than Count.
• BagEnumerator.Reset throws NotSupportedException

The class now implements ICollection, IList, IReadOnlyCollection, IReadOnlyList, ICollection and IList.
For the messages in the Exceptions I used those that are thrown by List.

If you are interested in these changes, please let me know in this discussion. If any other changes are needed, I will make them.