Refactor logging to remove logger, use fluentd with kubernetes filter (#380)

Remove the `logger` container from the logging daemonset. 

Remove the outgoing call from the poolmgr to the logger.  Use Fluentd's Kubernetes filter to add function name and UID to influx metadata.  

This means fluentd now figures out when to start collecting function logs on its own, without being informed by poolmgr.  This is great for other execution strategies, and for autoscaling, where fission isn't in direct control of function pod creation.

Also adds an integration test to make sure logging keeps working.

test/test_utils.sh

@@ -56,6 +56,19 @@ build_builder() {
     popd
 }
 
+build_and_push_fluentd(){
+    image_tag=$1
+
+    pushd $ROOT/logger/fluentd
+    docker build -t $image_tag .
+
+    gcloud_login
+
+    gcloud docker -- push $image_tag
+    popd
+
+}
+
 build_and_push_env_runtime() {
     env=$1
     image_tag=$2
@@ -110,11 +123,12 @@ helm_install_fission() {
     fetcherImageTag=$5
     controllerNodeport=$6
     routerNodeport=$7
+    fluentdImage=$8
 
     ns=f-$id
     fns=f-func-$id
 
-    helmVars=image=$image,imageTag=$imageTag,fetcherImage=$fetcherImage,fetcherImageTag=$fetcherImageTag,functionNamespace=$fns,controllerPort=$controllerNodeport,routerPort=$routerNodeport,pullPolicy=Always,analytics=false
+    helmVars=image=$image,imageTag=$imageTag,fetcherImage=$fetcherImage,fetcherImageTag=$fetcherImageTag,functionNamespace=$fns,controllerPort=$controllerNodeport,routerPort=$routerNodeport,pullPolicy=Always,analytics=false,logger.fluentdImage=$fluentdImage
 
     helm_setup
 
@@ -280,6 +294,8 @@ install_and_test() {
     imageTag=$2
     fetcherImage=$3
     fetcherImageTag=$4
+    fluentdImage=$5
+    fluentdImageTag=$6
 
     controllerPort=31234
     routerPort=31235
@@ -288,7 +304,7 @@ install_and_test() {
 
     id=$(generate_test_id)
     trap "helm_uninstall_fission $id" EXIT
-    if ! helm_install_fission $id $image $imageTag $fetcherImage $fetcherImageTag $controllerPort $routerPort
+    if ! helm_install_fission $id $image $imageTag $fetcherImage $fetcherImageTag $controllerPort $routerPort $fluentdImage:$fluentdImageTag
     then
 	dump_logs $id
 	exit 1