Testing that a tag exist or is assigned to the current entry isn't important in the tag controler since the `assignTagsToEntry` is already doing that job.
So it simplify the controller.
- convert english translation to translate key
- remove baggy template for login (never used since user isn't logged in and it'll use the default theme: material)
- fix tests about text in response (now checking translation key instead of translated text)
- remove all ugly `<div class="hidden">{{ form_rest(form) }}</div>`
Ensure that created use during install command will always be unique.
We assume that the install command must be run to initialize a wallabag instance. NEVER to add more user.
Also, use a better way to retrieve the real name of the database and not the one defined in parameters.yml (which isn't the same for test envi because the dbname isn't defined in parameters.yml but directly in config_test.yml)
