split up installing static webserver and riot copy

so we can just do the latter for the e2e tests on CI

test/end-to-end-tests/riot/install-webserver.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+set -e
+
+BASE_DIR=$(cd $(dirname $0) && pwd)
+cd $BASE_DIR
+# Install ComplexHttpServer (a drop in replacement for Python's SimpleHttpServer
+# but with support for multiple threads) into a virtualenv.
+(
+    virtualenv -p python3 env
+    source env/bin/activate
+
+    # Having been bitten by pip SSL fail too many times, I don't trust the existing pip
+    # to be able to --upgrade itself, so grab a new one fresh from source.
+    curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
+    python get-pip.py
+    rm get-pip.py
+
+    pip install ComplexHttpServer
+
+    deactivate
+)