[Feature]: Push data source to preview from pasted json or a pushed request

[mlumia]

Feature description

With the PUSH data source, it would be nice to allow showing the preview data from pasted json. Alternative (and better option) would be to allow pushing data to the endpoint which can be displayed in the preview data.

[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.