Merge branch 'feature/backend_couchdb' into 'master'

.gitlab-ci.yml

aas/backend/__init__.py

aas/backend/backends.py

aas/backend/couchdb.py

aas/model/base.py

test/backend/__init__.py

test/backend/test_backends.py

test/backend/test_couchdb.py

test/model/test_base.py