Use css loading animation and not gif

[skjnldsv]

Good:

Bad:

[nickvergessen]

You need to commit using commit -s, so it adds your signature:
https://github.com/nextcloud/server/blob/master/CONTRIBUTING.md#sign-your-work

You can also amend the signature manually afterwards:
git commit --amend and then add the line:
Signed-off-by: Random J Developer <random@developer.example.org>

on a new line at the end of your commit message.

[nickvergessen]

👍 for the change

[juliusknorr]

👍