password in resetPassword() not URL encoded

[Rillke]

First I'd like to apologize for reporting here as it is a customization issue; it seems to be impossible for me to get an account at https://git.thm.de

In https://git.thm.de/arsnova/arsnova-customization/blob/master/src/main/webapp/account.html#L280 it seems you send the new password not url encoded. Users may type %20 or similar in their passwords and do not expect they have to fill a white space at next login time. To mitigate this issue, I suggest e.g. copying jQuery.post. It takes care of this and a lot more, e.g. the issue reported in thm-projects/arsnova-backend#36

[Rillke]

On arsnova.eu, there is additionally (b.) the issue that the reset button is greyed out and (c.) you are redirected to https://arsnova.thm.de/blog/ after logging in.

Steps to reproduce on arsnova.eu:

• Go to https://arsnova.eu/mobile/
• Press Dozent/in
• Press ARSnova
• Register and reload this page (F5).
• Click "Passwort vergessen" and get a reset link
• Open the reset link from your inbox
• You can fill in passwords now but you can't submit the form. (b.) Fill in no%20Space as the new password in both fields.
• Open a DOM inspector and remove the disabled attribute from the submit button. Submit the form.
• Now enter your e-Mailaddress and no Space as the password (a.) and submit.
• You end up at https://arsnova.thm.de/blog/ (c.)