Institution admin and staff role updates behave
differently from site admin and staff ones.

(cherry picked from commit 9abbc8d0)

Bug 1846994: Mozilla Backpack needed to be deprecated
as it doesn't exist any more

See merge request !6

New feature in Mahara 20.04: Cover images for pages
and collections to brighten up the 'Pages and
collections' overview page (Bug #1870444).

and move the page to its correct place in the navigation.

New feature in Mahara 20.04: You can move your account
if you are moving to an SSO institution (Bug #1846412).

and update screenshots to reflect these changes.

New features in Mahara 20.04:

Bug #1855383 Create new user_roles system where you
    can assign custom roles to a user
Bug #1855556 Allow minimum information when creating
    a user via SAML
Bug #1855560 Allow SAML auth to set admin/staff roles
    on create user
Bug #1855622 Allow SAML to create institution if it
    doesn't exist before adding new user to it
Bug #1859120 Allow a 'parent' saml auth instance update
    the roles for all the similiar instances

New feature in Mahara 20.04: Institution short name can
contain letters and numbers and can be as short as one
character (Bug #1855344).

New feature in Mahara 20.04: turn on logging of
SAML attributes (Bug #1855327).

New in Mahara 20.04: SSO login buttons are displayed
more prominently (Bug #1855358).

New feature in Mahara 20.04: Delete all ements of
a standard or children elements of a standard element
in one go (Bug #1856260).

There are still a few more instances of removing 'user'
to go through, and all screenshots still need to be changed.

I also changed double quotation marks to single ones
where necessary to move to the new style.

New experimental feature in Mahara 20.04:
Export portfolios and entire accounts as PDFs
(Bug #1826284).

New feature in Mahara 20.04: You can export accounts
in bulk now in all available export formats (Bug #1825231).

New feature in Mahara 20.04: Combined export of all
available export options (Bug #1853069).

New feature in Mahara 20.04: All export options are
combined into one export zip archive (Bug #1853069).

New feature in Mahara 20.04: Add personal labels to
groups in order to be able to filter for them in
various places in Mahara:
- Groups overview page
- Profile page
- Profile sidebar

(Bug #1848092)

and also change 'user' to a more appropriate term

New feature in Mahara 20.04: Site administrators
determine the default group settings, which can
then still be changed by group administrators
(Bug #1855333).

New feature in Mahara 20.04: Restrict what file types
can be uploaded (Bug #1855351).

New feature in Mahara 20.04: When a page has been
signed off but the peer assessor hasn't made their
assessment yet, they see an alert to that effect
(Bug #1857934).

New in Mahara 20.04: You see when a page was signed off
and verified (Bug #1857929).

New feature in Mahara 20.04: Be able to change the
owner of an external service to be more independent
of the site admin (Bug #1852644).

That also meant updating cross references for sections
that now don't exist anymore.

The re-organisation of the categories was long overdue.
Now with the change from 'user' to something else, it was
a good opportunity to tackle the re-organisation.

and removed old 19.10 images from the 'New' section.