Render HTML contained in messages

[kofrezo]

For some messages it is useful to render the HTML such as for example if you have multiple messages and want to display them as list.

[lamaral]

It LGTM.
I will wait to hear what @zados says, as I see a potential for XSS.

[zados]

@lamaral is correct, this makes a XSS certainly possible, as we do not escape HTML anymore.
@kofrezo stated that all messages are supplied through the code itself and do not contain user input, therefore this is acceptable to me. However it has to be ensured that no user supplied input can make it's way here.

If this cannot be ensured or we need to put user input into the message, we should not merge this or revert this in the future should user input be required then.