Improve Python configuration for LGTM

LGTM is no longer able to analyse all Python code without importing it.
Define OS and Python package dependencies and build the project for
Python, too.

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>

contrib/lgtm_container.py

@@ -0,0 +1,36 @@
+#!/usr/bin/python3
+"""Helper script to test LGTM config
+
+$ contrib/lgtm_container.py > Dockerfile
+$ docker build -t lgtm .
+"""
+import os
+import yaml
+
+LGTM_YML = os.path.join(os.path.dirname(__file__), '..', '.lgtm.yml')
+
+
+def main():
+    with open(LGTM_YML) as f:
+        cfg = yaml.safe_load(f)
+
+    python = cfg['extraction']['python']
+
+    print("""\
+    FROM ubuntu:bionic
+    RUN apt-get update && \
+        apt-get install -y {dpkg} python3-venv && \
+        apt-get clean
+    RUN python3 -m venv /venv
+    RUN /venv/bin/pip install wheel
+    RUN /venv/bin/pip install {pypkg}
+    ADD . /freeipa
+    RUN cd /freeipa && ./autogen.sh --with-ipaplatform=debian
+    """.format(
+        dpkg=' '.join(python['prepare']['packages']),
+        pypkg=' '.join(python['python_setup']['requirements'])
+    ))
+
+
+if __name__ == '__main__':
+    main()