Fix templates

See merge request !478

Resolve "Change password"

See merge request !474

Merge branch '354-change-password' of edugit.org:AlekSIS/Official/AlekSIS-Core into 354-change-password

Resolve "Provide request in DashboardWidget.get_context"

Closes #352

See merge request !452

Set password of LDAP-logged-in user in database

See merge request !475

Having a local password is needed to make changing passwords easier. In
order to catch password changes in a universal way and forward them to
backends (like LDAP, in this case), getting the old password first is
necessary to authenticate as that user to LDAP.

We buy the small insecurity of having a hash of the password in the
Django database in order to not require it to have global admin permissions
on the LDAP directory.

In addition, we fail early by raising PermissionDenied if LDAP cannot
authenticate the user, so as to not allow logins with ghost users that
were removed in LDAP or changed their password there.

Resolve "Customise django-colorfield for use with Materialize"

Closes #366

See merge request !473

Add SuccessNextMixin for automatic redirecting after finishing an action

See merge request !471

Some JS and CSS were added, too.

Add template for pull requests at GitHub for mirroring

See merge request AlekSIS/official/AlekSIS-Core!472

Resolve "Add possibility to upload files via CKEditor"

Closes #364

See merge request !470

Resolve "Provide landscape print template"

Closes #311

See merge request !469

Update poetry.lock

See merge request !466

Merge branch '333-add-possibility-to-manage-object-level-permissions-for-group-and-person-models-in-admin' into 'master'

Resolve "Add possibility to manage object-level permissions for Group and Person models in admin interface"

Closes #333

See merge request !418

Include support for icons in Materialize chips template

See merge request !462

Resolve "CSS arrows for django-tables2 materialize"

Closes #358

See merge request !465

Make help text in Materialize forms smaller

See merge request !463