Make the Emails more usefull: Dynamic Ignore feature

[Andreas-Schoenefeldt]

Emails about warnings or errors, that have no critical content, are rather informational and can be ignored.

In order to limit the amount of emails and make them more useful, every email should contain an "Ignore Error" link. The link triggers a function, which is (based on the md4 error identifier) adding the error to some kind of ignore list. I would prefer an online database like https://parse.com/ but it is also thinkable to build this as some kind of local textfile or database.

The beauty about parse.com is, that we would not have to make some kind of web hook available on our server, but could simply rely on the parse javascript data.