Merge branch 'cleanup_toolchains' into 'django3_migration'

beat/web/toolchains/__init__.py

beat/web/toolchains/admin.py

beat/web/toolchains/api.py

beat/web/toolchains/apps.py

beat/web/toolchains/migrations/0001_initial.py

beat/web/toolchains/models.py

beat/web/toolchains/serializers.py

beat/web/toolchains/signals.py

...lchains/templates/toolchains/dialogs/import_settings.html

beat/web/toolchains/templates/toolchains/diff.html

beat/web/toolchains/templates/toolchains/list.html

beat/web/toolchains/templates/toolchains/panels/actions.html

beat/web/toolchains/templates/toolchains/panels/editor.html

beat/web/toolchains/templates/toolchains/panels/sharing.html

beat/web/toolchains/templates/toolchains/panels/table.html

beat/web/toolchains/templates/toolchains/panels/viewer.html

beat/web/toolchains/templates/toolchains/view.html

beat/web/toolchains/templatetags/toolchain_tags.py

beat/web/toolchains/views.py