Provide ability to override options used to serialize, use default op…

[modios]

An alternative implementation so we can use custom properties for the serializer.
This has several differences compared to #285.
Please let me know which one you prefer so we can decline the other PR and try to merge the one chosen (if we are happy with any of them).

[rossmills99]

I prefer this to the other set of changes; it provides a means to set default serializer settings as well as override them in the specific places where user-specified data is supplied.

There's one use case that might not be covered which is setting a user-specified object in an AQL query bind-params. For example:

var response = await _cursorApi.PostCursorAsync<MyModel>(
                "INSERT @obj IN Collection",
                new Dictionary<string, object> { ["obj"] = new MyClass() });

We added specific handling for that case because we wanted to avoid changing the bind vars during serialization, since that's obviously confusing when you come to use the keys in the query. @DiscoPYF might remember better the specifics of what that issue was about, did I get it right?

Anyway I've left a few comments about typos in the PR.

The last thing is that the readme should be updated to reflect changes in the Quick Start guide and to add some documentation about how to set default serializer settings in serializer implementations.

[DiscoPYF]

I also prefer this approach to the other pull request. The functionality brought by those changes is great. Thanks @modios

I left a bunch of comments. I would appreciate if we can go over those.

[DiscoPYF]

@modios Thanks for updating. I left a few more comments but they don't go in the way of merging this, so I have approved. 👍

[DiscoPYF]

fix #276
fix #203

[rossmills99]

This is looking good! The only thing missing is an update in the readme to reflect the new options and changes. I was going to recommend some changes, but since I've gone to the effort of reading the doc again I'll just push a new commit with what I would otherwise be proposing.