Provide reporting feature to mediators

[chimp1984]

Mediators need to make a report of their cases to provide evidence for their work done and to give feedback to developers and UX experts to improve Bisq to lower the cases.
As @bisquser stated in bisq-network/roles#83 (comment) it is not clear to them how to provide a report. We have a shortcut built in for copying all dispute cases to the clipboard but that contains all the communications and way too much private data to be suited to get added to the report. Creating manually such a report is quite a bit of effort.

We should add another shortcut (or button) for exporting the case in a format we want to see in the reports. Here is a rough suggestion.

Dispute nr: [using enumeration instead of trade ID should be better for privacy and enough to keep cases identifiable]
Reason for dispute: [Bug, "future trade", bank problems, Usability, Other,...]
Summary: [Short summary notes as alreayd used. Mediators need to avoid to add private information in there and to make it informative enough to get an idea what the dispute was about]
Opening date:
Closinging date:

I think all that data is easy accessible inside the dispute domain and it should be a easy task to implement that and will help to improve and standardize reporting. i think we do not need a data filter as the mediator can easily delete the already reported past cases from the text.

A proof system for disputes might be tricky and would require probably some mechanism that traders are publishing information and that needs to match the information provided by mediators. I don't see this a high priority in the current state. Much more important is that feedback from mediators goes into improvements so that total dispute cases get reduced.

Btw. All the above would be good for the refund agent as well. As it shares the same code structures it should be trivial to extend that.