Lower session time and add "Remember me" option to log in form

[frjo]

For improved security we should lover the default session time.

• [x] Set default SESSION_COOKIE_AGE to 12 hours.
• [x] Set default SESSION_COOKIE_AGE_LONG to two (2) weeks.
• [x] Add "Remember me" checkbox to login form, Hypha then uses SESSION_COOKIE_AGE_LONG.

Some questions:

1. Can we make it work with passwordless login?
2. If you login with Google, what session time should we set?

[frjo]

See initial discussion at https://github.com/HyphaApp/hypha/issues/3890