Add rsync so the ui can build again

Also add back the init target to the ui-v2 makefile

build-support/docker/Build-UI.dockerfile

@@ -6,7 +6,7 @@ ARG MAKE_VERSION=4.2.1-r0
 ARG YARN_VERSION=1.7.0
 
 RUN apk update && \
-    apk add nodejs=${NODEJS_VERSION} nodejs-npm=${NODEJS_VERSION} make=${MAKE_VERSION} && \
+    apk add nodejs=${NODEJS_VERSION} nodejs-npm=${NODEJS_VERSION} make=${MAKE_VERSION} rsync && \
     npm install --global yarn@${YARN_VERSION} && \
     mkdir /consul-src
 

ui-v2/GNUmakefile

@@ -7,6 +7,9 @@ dist:
 	yarn run build
 	mv dist ../pkg/web_ui/v2
 
+init:
+	yarn install
+
 lint:
 	yarn run lint:js
 format: