Add survey about which dependencies are already in Debian.

docs/dev/04_debian_survey.txt

+[BiscuIT-ng]
+- python3-babel
+! beautifulsoup4
+- python3-click
+- python3-colour
+- python3-configobj
+- python3-django
+! django-any-js
+- python3-django-appconf
+- python3-django-auth-ldap
+! django-bootstrap4
+- python3-django-contact-form
+- python3-django-debug-toolbar
+! django-easy-audit
+! django-fa
+! django-image-cropping
+- python3-django-impersonate
+- python3-django-ipware
+! django-maintenance-mode (python3-django-maintenancemode ist was anderes‽)
+! django-menu-generator
+! django-middleware-global-request
+! django-phonenumber-field
+- python3-django-sass-processor
+! django-settings-context-processor
+! django-stubs
+- python3-django-tables2
+! dynaconf
+! easy-thumbnails
+- python3-phonenumbers
+- python3-pil [pillow]
+- python3-pyasn1
+- python3-pyasn1-modules
+! python-box
+- python3-dotenv
+- python3-ldap
+! python-memcached
+- python3-tz [pytz]
+- python3-yaml [pyyaml]
+- python3-six
+- python3-soupsieve
+- python3-sqlparse
+- python3-toml
+
+[BiscuIT-App-Alsijil]
+% BiscuIT-ng
+% BiscuIT-App-Chronos
+
+[BiscuIT-App-Chronos]
+% BiscuIT-ng
+
+[BiscuIT-App-Exlibris]
+% BiscuIT-ng
+! django-isbn-field
+- python3-isbnlib
+! isbnlib-dnb
+! pylabels
+- python3-reportlab
+
+[BiscuIT-App-SchILD-NRW]
+% BiscuIT-ng
+- python3-pandas
+- python3-phonenumbers (redundant, BiscuIT-ng dependet da schon drauf)
+
+[BiscuIT-App-Untis]
+% BiscuIT-ng
+% BiscuIT-App-Chronos