Build wheel cache for venvs

Building a bunch of virtual envs later is going to be tedious if we do not
pre-cache certain annoying-to-build packages.

* tools/build_wheels.sh: pre-build some wheels for annoying package installs
* list distro package dependencies in files/*/venv
* list packages to pre-build as wheels in files/venv-requirements.txt
* install database Python modules when setting up the database

Change-Id: Idff1ea69a5ca12ba56098e664dbf6924fe6a2e47
diff --git a/files/rpms/devlibs b/files/rpms/devlibs
new file mode 100644
index 0000000..6010c9f
--- /dev/null
+++ b/files/rpms/devlibs
@@ -0,0 +1,8 @@
+libffi-devel  # pyOpenSSL
+libxml2-devel  # lxml
+libxslt1-devel  # lxml
+mariadb-devel  # MySQL-python  f20,f21,rhel7
+mysql-devel  # MySQL-python  rhel6
+openssl-devel  # pyOpenSSL
+postgresql-devel  # psycopg2
+python-devel  # pyOpenSSL