Add button to download all errors/crashes of an app

[enloc-port]

As an AppCenter user, I want to be able to download all crash/error reports of an app, preferably as a CSV or JSON file. For that, I'd like to have a "Download all issues" button in the top right corner of the Diagnostics -> Issues screen, just like there is when opening a single error/crash report.

The alternative would be to go into every single crash/error report and download it to be able to search them all for a specific one by specific criteria. This is highly inconvenient and inefficient.

As of now, it is only possible to download a single crash/error report using the "Download" button in the top right of the screen. But since we sometimes have the need to find a specific error report based on specific criteria (like some error properties), it is almost impossible for us right now to find the error we are looking for.