Add BulkExecutionEnabled to CosmosDbContextOptionsBuilder

[JoasE]

Implements: #36599

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[JoasE]

Pipeline appears to have an error running EFCore.InMemory.FunctionalTests but they succeed locally.

[AndriySvyryd]

Can you also add some functional tests, including ones that combine bulk execution with batching or eTags?

[JoasE]

@AndriySvyryd I don't think any behavior from cosmos or the sdk changes when you enable bulk execution. I can add a tests that verify that? Basically inheriting from the tests that already exist and running those with bulk enabled

[JoasE]

I'm actually now realizing that this doesn't make a lot of sense. When using bulk, you probably want to execute the entries to save in parallel. Otherwise the only bulk that can happen is between different contexts. Will close this if you agree and see if I have time to implement that after #37027 is merged. (as it will probably have conflicts) I will have to think on how to best handle the parallelism (with manual session token management) and if we should only do in parallel with bulk or maybe increase parallelism without as well. (but probably only with bulk)