Accounts: support for external users

[Nick Chadwick]

Add support for inviting external users to sign up for an account, and for
them to reset their password. (This facilitates use of IVLE in a wider
variety of contexts).

[Steven Bird (stevenbird)]

How about using their email address as the account name?

There should also be a configuration setting that allows people to request an
account, by submitting a form.

How will such people discover IVLE worksheets, when they're not enrolled in a subject?

[William Grant (wgrant)]

People may already change their passwords, if they have a local password (ie. they're
not an LDAP account). In the current permissions model, they *need* to be enrolled in
the subjects, but we can easily add an automated enrolment module that magically
enrols all non-LDAP users in some offering.

[Matt Giuca (mgiuca)]

Issue 139 has been merged into this issue.

[Matt Giuca (mgiuca)]

The ability to 'sign up' is optional (and disabled in the University install). We
want this on the demo site (which we want up by Release 1.0).

This page includes a box where a user can describe why they are interested
in IVLE. This allows a human to manually approve a sign-up request and
minimize bogus account creation.