Feature: async transaction scope support

[huer12]

As suggested in #5629

I added a version for a async ITransactionScope

[CLAassistant]

All committers have signed the CLA.

[michaelstaib]

Hey there,

thank you for contributing.

The change you are proposing is a major change to Hot Chocolate and cannot be included into Hot Chocolate 15 or earlier. I am also wondering if we should even have this scope formalized in the first place. It might be better to remove it with 16 and rework the pipeline in a way that such a feature can be easily added by users them selfs.

In any case, I converted this PR to a draft and it will take a while before we look at it as we are at the moment working on the foundations of 16, we have not yet started looking at the request execution pipeline itself. I think after August most of the foundation pieces will be in place and the core team will have some time to discuss transaction scopes.

[huer12]

Hi
I do agree, that it may would make sense to rework the pipeline, but I do not understand why it is a major change. I made t in a non breaking way. Therefore it would not be a problem to add it to version 15.
I would appreciate if you would have look at it again. It would be important for us to have this feature sooner.

[michaelstaib]

OK, It looked as if you replaced it completely but instead you added to it. I only skimmed over it...

In any case we will not do an change on this in 15 and will have as I pointed out a look at this whole thing with V16 which is coming this year. I do not want to introduce something that we actually want to do differently.