Move docker healthcheck into dedicated script.

docker/healthcheck.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# If the port is not specified as env var, take it from the config file
+if [ -z ${CONDUIT_PORT} ]; then
+  CONDUIT_PORT=$(grep -m1 -o 'port\s=\s[0-9]*' conduit.toml | grep -m1 -o '[0-9]*')
+fi
+
+# The actual health check.
+# We try to first get a response on HTTP and when that fails on HTTPS and when that fails, we exit with code 1.
+# TODO: Change this to a single curl call. Do we have a config value that we can check for that?
+curl --fail -s "http://localhost:${CONDUIT_PORT}/_matrix/client/versions" || \
+    curl -k --fail -s "https://localhost:${CONDUIT_PORT}/_matrix/client/versions" || \
+    exit 1