[accounts] updated templates - text correction and added grant supervisor access…

See merge request !229

[accounts] updated templates - text correction and added grant supervisor access button inside box when available

Closes #479

See merge request !228

[plotters] added URL_PREFIX=context['URL_PREFIX'] in dict returned by plotters templatetags. Fixes #479

See merge request !227

[ui/doc] added link to supervisor registration and updated documentation faq on supervisor registration

[scripts] scheduler.py: Importation of beat.web modules must be done after the call to django.setup()

Use getById to query for non-conforming id strings

Closes #478

See merge request !226

Update user documentation for the reports changes

See merge request !225