Add report feature for disputes

[chimp1984]

At the dispute views (mediator, refund agent both for trader and
dispute agents) the shortcut cmd+k (or crtl+k or alt+k) will open a
popup displaying all disputes as compact summary. A copy to clipboard
button make it easy to copy the text to a text editor and post the
relevant disputes for the mediators/refund agents report.

Fixes #3788

[chimp1984]

Here is a example of the report format:

Dispute nr. 1
Opening date: 25 Nov 2019 11:52:08
Close date: 26 Nov 2019 12:04:54
Duration: 23 hours, 58 minutes
Summary notes: Buyer did not start payment.
Summary notes (trader 2): Buyer did not pay. Seller will get buyer's security deposit.
Reason: PROTOCOL_VIOLATION

Dispute nr. 2
Opening date: 12 Dec 2019 23:07:21
Close date: 13 Dec 2019 21:08:03
Duration: 22 hours, 58 minutes
Summary notes: Deposit tx was not published
Reason: BUG

Summary of reasons for disputes:
PROTOCOL_VIOLATION: 1
BUG: 1

I did not include trade ID for privacy reasons, but that's up for discussion if that should be added.

The summary notes are usually the same but the mediator/refund agent can send different summary notes as well. Only in that case we show both ("Summary notes (trader 2)").

[ripcurlx]

ACK

Although it might not be super intuitive that the clipboard contains everything and only the UI shows the truncated version, I think it is good enough for a start.

[chimp1984]

Although it might not be super intuitive that the clipboard contains everything and only the UI shows the truncated version, I think it is good enough for a start.

Its only for mediators...