Password toggle login

Currently the toggle is in 3 places, always for the password field:
1. Installation page for choosing a password (and for the probably complex database password)
2. Log in page for putting in your password
3. Personal settings for changing a password (the »current password« field does not have it)

Now the installation page and the personal settings need this switch so you can double-check the password you just decided. But the log in page actually does not need it. So let’s just cut it there.

cc @raghunayyar @DeepDiver1975 @nono-gdv @kabum @karlitschek @MTRichards