[#108] Add reset password hooks

[matthewhilton]

Closes #108

Since core does not send password reset emails to suspended accounts, I configured a hook in auth_enrolkey to send them itself if:

1. unsuspendaccounts is enabled [1]
2. User is using enrolkey
3. User is suspended

This works, but the user gets logged in after resetting their password despite still being suspended.

So I also added a post set password request hook where if:

1. The user is using enrolkey
2. The user is suspended

They are logged out immediately

This ends up with the desired flow:

1. User is using enrolkey, but is suspended
2. They request a password reset
3. Password reset email is delivered (via new hook)
4. User resets password and continues
5. User is logged out (via new hook)
6. User logs in using username + newly reset password
7. User is redirected to unsuspend.php (existing) since they are suspended
8. User is prompted to enter username + password + enrolkey to unsuspend account

[1]

On the login, if a user is suspended, and is using the enrolkey authentication type, redirect them to an intermediate page which asks for their username, password and enrolkey to un-suspend them

TODO

• Unit tests ?
• CI fixed