docker: include default snippets onto Dockerfile, allow multiple snippets folders, closes #8

Dockerfile

@@ -32,6 +32,7 @@ RUN test -e "${GOBIN}/go-away"
 FROM --platform=$TARGETPLATFORM ${from}
 
 COPY --from=build /go/bin/go-away /bin/go-away
+COPY examples/snippets/ /snippets/
 
 ENV TZ UTC
 
@@ -65,7 +66,7 @@ ENV JWT_PRIVATE_KEY_SEED="${GOAWAY_JWT_PRIVATE_KEY_SEED}"
 ENTRYPOINT  /bin/go-away --bind "${GOAWAY_BIND}" --bind-network "${GOAWAY_BIND_NETWORK}" --socket-mode "${GOAWAY_SOCKET_MODE}" \
             --metrics-bind "${GOAWAY_METRICS_BIND}" --debug-bind "${GOAWAY_DEBUG_BIND}" \
             --config "${GOAWAY_CONFIG}" \
-            --policy "${GOAWAY_POLICY}" --policy-snippets "${GOAWAY_POLICY_SNIPPETS}" \
+            --policy "${GOAWAY_POLICY}" --policy-snippets "/snippets" --policy-snippets "${GOAWAY_POLICY_SNIPPETS}" \
             --client-ip-header "${GOAWAY_CLIENT_IP_HEADER}" --backend-ip-header "${GOAWAY_BACKEND_IP_HEADER}" \
             --cache "${GOAWAY_CACHE}" \
             --challenge-template "${GOAWAY_CHALLENGE_TEMPLATE}" --challenge-template-theme "${GOAWAY_CHALLENGE_TEMPLATE_THEME}" \