Better login redirect in emails

[Kristina Hoeppner]

(Bug 1856261 is an extension to this)

On a multi-tenanted Mahara site, there can be many authentication methods in play. However, the link that people receive in notifications, e.g. to reply to forum posts or view their messages from other people is always the same and if not already logged in redirects them to the normal Mahara login page.

Then people try to log in but fail as they don't have internal or LDAP auth but SAML, MNet or LTI or something else.

Institution-specific redirects are needed to allow for the specifying of the login URL. Currently, this is only possible to set site wide.

The site has the ability to set a variable in email links so that the institution is passed along for Mahara to determine the primary authentication method and if needed redirect to the appropriate login screen.