Added LevelDB-based attribute container store

Author: joachimmetz

.github/workflows/test_docs.yml

@@ -36,7 +36,7 @@ jobs:
         add-apt-repository -y ppa:deadsnakes/ppa
         add-apt-repository -y ppa:gift/dev
         apt-get update -q
-        apt-get install -y build-essential git  python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
+        apt-get install -y build-essential git python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
     - name: Install tox
       run: |
         python3 -m pip install tox

.github/workflows/test_tox.yml

@@ -44,7 +44,7 @@ jobs:
         add-apt-repository -y ppa:deadsnakes/ppa
         add-apt-repository -y ppa:gift/dev
         apt-get update -q
-        apt-get install -y build-essential git  python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
+        apt-get install -y build-essential git python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
     - name: Install tox
       run: |
         python3 -m pip install tox
@@ -80,7 +80,7 @@ jobs:
         add-apt-repository -y ppa:deadsnakes/ppa
         add-apt-repository -y ppa:gift/dev
         apt-get update -q
-        apt-get install -y build-essential git  python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
+        apt-get install -y build-essential git python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
     - name: Install tox
       run: |
         python3 -m pip install tox
@@ -118,7 +118,7 @@ jobs:
         add-apt-repository -y ppa:deadsnakes/ppa
         add-apt-repository -y ppa:gift/dev
         apt-get update -q
-        apt-get install -y build-essential git  python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
+        apt-get install -y build-essential git python${{ matrix.python-version }} python${{ matrix.python-version }}-dev python${{ matrix.python-version }}-venv python3-distutils python3-pip python3-setuptools python3-yaml
     - name: Install tox
       run: |
         python3 -m pip install tox