HELIO-2064 - Fix up default login redirect
HELIO-2064 - Fix up default login redirect

- Redirect to the SP, rather than /shib_login in the production fallback
- Move the default entity ID to the sp_login_url to catch all cases
- Skip storing user location for all sessions controller actions

Note that this change should eliminate the need for the `default_login`
action entirely. It should be removed and links updated to use /login.

mlibrary/heliotrope,mlibrary/heliotrope,mlibrary/heliotrope,mlibrary/heliotrope