Allow the login box to adjust if there are both internal and external login options available

[Robert Lyon]

Currently if we are using an external authentication such as SAML we place a 'SSO' button above the internal login form in the login box.

This can confuse users as they try to login with their IdP login credentials in Mahara's login box instead of following the button and logging in at their IdP as 'SSO' is a generic ' confusing label

Planned changes are:

- hide the internal login form within a collapsible area if there are both external and internal login options available
- allow external SAML auth to show a better label for the IdP login
- if there are multiple SAML auth options show as 2 or 3 then show buttons for all
  - if there are more than 3 then show generic SAML button to allow them to choose IdP (but with better label)

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/10646

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/10646
Committed: https://git.mahara.org/mahara/mahara/commit/1c22867ce3f49aff32db52645a718ec9998d4303
Submitter: Cecilia Vela Gurovic (<email address hidden>)
Branch: master

commit 1c22867ce3f49aff32db52645a718ec9998d4303
Author: Robert Lyon <email address hidden>
Date: Fri Dec 6 14:15:20 2019 +1300

Bug 1855358: Update the login box

Allow the internal login form to be in a collapsible area if there are
both internal and external login options

Don't show the generic 'fields are required' message when internal
form is hidden in collapse field

behatnotneeded

Change-Id: Ib097f5f33c9f9a85bc91bdd88df04e21d9c1a3e3
Signed-off-by: Robert Lyon <email address hidden>