[Feature]: support of _inc in graphql

[nosovk]

Feature description

It's hard to build idempotence interaction with Datahub.
Mostly because there is only input method, which equals to set.
Graphql provides _inc method, some example here.
Supporting it will allow to create counters that wouldn't broke if we have few clients to sync.

[github-actions]

Thanks a lot for reporting the issue. We did not consider the issue as "Pimcore:Priority", "Pimcore:ToDo" or "Pimcore:Backlog", so we're not going to work on that anytime soon. Please create a pull request to fix the issue if this is a bug report. We'll then review it as quickly as possible. If you're interested in contributing a feature, please contact us first here before creating a pull request. We'll then decide whether we'd accept it or not. Thanks for your understanding.