[BUG?]: Create mountpoint for /externals/ (#203)

* runner/controller: Add externals directory mount point

* Runner: Create hack for moving content of /runner/externals/ dir

* Externals dir Mount: mount examples for '__e/node12/bin/node' not found error

runner/entrypoint.sh

@@ -43,6 +43,9 @@ fi
 cd /runner
 ./config.sh --unattended --replace --name "${RUNNER_NAME}" --url "${GITHUB_URL}${ATTACH}" --token "${RUNNER_TOKEN}" ${RUNNER_GROUP_ARG} ${LABEL_ARG}
 
+# Hack due to the DinD volumes
+mv ./externalstmp/* ./externals/
+
 for f in runsvc.sh RunnerService.js; do
   diff {bin,patched}/${f} || :
   sudo mv bin/${f}{,.bak}