Improve login view
- improve visual design to fix #1355
- add option to redirect user to SSO if a sole SSO provider is configured
in the near future I'd amend to this with the option to provide a custom logo
coverage: 85.219% (+0.2%) from 84.979% when pulling f59d49d7e4f00ccaa57e100de19387b44b7f50c9 on sole-provider-redirect into d485a4ef6539a555bd97af84ceea233f0c5a16b6 on main.
IMO this has the same problem as the current layout regarding the non-alignment of SSO button and form, just with the colums inverted. I would prefer smth as suggested in https://github.com/ephios-dev/ephios/issues/1355#issuecomment-2344253676
While we are at it with the login: we should provide a proper error message when entering wrong login credentials. Currently the form only says "Please enter a correct email address and password. Note that both fields may be case-sensitive."
