Add gcc compiler in base stack (#338)

The gcc is installed inbuild-essential by apt in order to support installing pypi packages that need build such as `pymatgen` and for Cython. 
The size of full-stack increased 200MB.

Author: unkcpz

stack/base/Dockerfile

@@ -4,6 +4,14 @@ FROM ${BASE}
 LABEL maintainer="AiiDAlab Team <[email protected]>"
 
 USER root
+
+RUN apt-get update --yes && \
+    apt-get install --yes --no-install-recommends \
+    # for apps which need to install pymatgen:
+    # https://pymatgen.org/installation.html#installation-tips-for-optional-libraries
+    build-essential && \
+    apt-get clean && rm -rf /var/lib/apt/lists/*
+
 WORKDIR /opt/
 
 ARG AIIDA_VERSION

tests/test_aiidalab.py

@@ -117,7 +117,7 @@ def test_install_apps_from_stable(aiidalab_exec, package_name, nb_user, variant)
 
 
 @pytest.mark.integration
-@pytest.mark.parametrize("package_name", ["aiidalab-widgets-base"])
+@pytest.mark.parametrize("package_name", ["aiidalab-widgets-base", "aiidalab-qe"])
 def test_install_apps_from_master(aiidalab_exec, package_name, nb_user, variant):
     if "lab" not in variant:
         pytest.skip()