fix: prevent endless waiting for response, without creating resources multiple times (DEV-2860)

[jnussbaum]

No description provided.

[linear]

DEV-2860 prevent endless waiting for response, without creating resources multiple times

Currently, PUT and POST requests in DSP-TOOLS don't have a timeout (ConnectionLive.put() and .post()). This is due to the retry-mechanism try_network_action(): If there is a timeout, there is a risk of duplicated resources in the xmlupload (see DEV-2412, #432).

However, we sometimes have the problem that an xmlupload can hang up itself. This is even worse than creating resources multiple times.

A tradeoff would be to set the timeout to 60 seconds.

To mitigate, a check should be added after the xmlupload is finished: count the number of resources on the server, and warn the user if there are more than in the XML file.

[gNahcab]

LGTM!