[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/Dockerfile

@@ -1,7 +1,7 @@
 FROM ubuntu:18.04
 
 ARG TARGETPLATFORM
-ARG RUNNER_VERSION=2.274.1
+ARG RUNNER_VERSION=2.274.2
 ARG DOCKER_VERSION=19.03.12
 
 ENV DEBIAN_FRONTEND=noninteractive
@@ -55,7 +55,7 @@ RUN export ARCH=$(echo ${TARGETPLATFORM} | cut -d / -f2) \
   && usermod -aG docker runner \
   && echo "%sudo   ALL=(ALL:ALL) NOPASSWD:ALL" > /etc/sudoers
 
-# Runner download supports amd64 as x64
+# Runner download supports amd64 as x64. Externalstmp is needed for making mount points work inside DinD.
 RUN export ARCH=$(echo ${TARGETPLATFORM} | cut -d / -f2) \
   && if [ "$ARCH" = "amd64" ]; then export ARCH=x64 ; fi \
   && mkdir -p /runner \
@@ -64,6 +64,7 @@ RUN export ARCH=$(echo ${TARGETPLATFORM} | cut -d / -f2) \
   && tar xzf ./runner.tar.gz \
   && rm runner.tar.gz \
   && ./bin/installdependencies.sh \
+  && mv ./externals ./externalstmp \
   && rm -rf /var/lib/apt/lists/*
 
 COPY entrypoint.sh /runner