Use render_pdf to generate full register printout

See merge request !179

Merge branch '139-lesson-topic-not-carried-to-previous-lesson-if-entered-in-second-lesson-of-a-block' into 'master'

Resolve "Lesson topic not carried to previous lesson if entered in second lesson of a block"

Closes #139

See merge request !169

Merge branch 'master' into 139-lesson-topic-not-carried-to-previous-lesson-if-entered-in-second-lesson-of-a-block

Denote Teckids e.V. as licensor as defined by EUPL

See merge request !178

This is important to clarify the jurisdiction and court location in case of
license disputes.

Prepare django 3.2 update

See merge request !177

Fix migration

See merge request !176

Update copyright information for 2021

See merge request !174

Update poetry.lock

See merge request !175

Merge branch 'master' into 139-lesson-topic-not-carried-to-previous-lesson-if-entered-in-second-lesson-of-a-block

Fix GlobalPermissionModel

See merge request !172

Avoid superfluous query for previous lesson in lesson.html

See merge request !171

Simplify getting of teacher names in _generate_dicts_for_lesson_periods

See merge request !170

It has been already fetched in the view.

Use only get_teachers in full register printout

See merge request !168

get_teachers will automatically select the correct teachers
without any need for further action

Resolve "Full register shows all persons of school (but without statistics)"

Closes #153

See merge request !167

Optimize object permission queries by using django-guardian's prefetch util

See merge request !165

Merge branch '151-get_or_create-for-lesson-documentations-and-personal-notes-doesn-t-work-correctly-because-of' into 'master'

Resolve "get_or_create for lesson documentations and personal notes doesn't work correctly because of missing unique index"

Closes #151

See merge request !166

Resolve "[SQL] Query for person statistics in week overview takes very long"

Closes #149

See merge request !164