The session secret is used to sign and authenticate the session cookie
and this way very important for the authentication process.
By default the session secret is set to `secret` and never changes. This
commit will add a generator for a dynamic session secret if it stays
unchanged.
It prevents session hijacking this way and will warn the user about
the missing secret.
This also implies that on a restart without configured session secret
will log out all users. While it may seems annoying, it's for the users
best.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
3599fb79b4