[feat] allow bypassing schema verification for tests

common/src/leap/soledad/common/couch/__init__.py

common/src/leap/soledad/common/couch/state.py

server/src/leap/soledad/server/__init__.py

testing/test_soledad/util.py

testing/tests/client/test_app.py

testing/tests/couch/test_atomicity.py

testing/tests/couch/test_command.py

testing/tests/server/test_server.py

testing/tests/sync/test_encdecpool.py

testing/tests/sync/test_sync.py

testing/tests/sync/test_sync_mutex.py

testing/tests/sync/test_sync_target.py