Add repository for devstack-plugin-prometheus

Currently prometheus installation is done by sg-core devstack
plugin. sg-core devstack plugin was used by ceilometer project.

Recently we have added prometheus datasource support in watcher
project. We also need to install pushgateway and node exporter
for testing.

Since sg-core devstack plugin repo is meant for sg-core related
stuff. So we will removing prometheus installation from sg-core
devstack plugin and moving it to new devstack-plugin-prometheus
repo.

devstack-plugin-prometheus repo will contain all the bits for
installation and configuration for prometheus, alert-manager,
node-exporter and pushgateway.

It will be used by ceilometer and watcher project and maintained
by QA, watcher and ceilometer devs.

Needed-By: https://review.opendev.org/c/openstack/governance/+/939953
Change-Id: I466ae8013bd4a9a298c6a70dadb292ea9fc6c50b
Signed-off-by: Chandan Kumar (raukadah) <chkumar@redhat.com>

gerrit/acls/openstack/devstack-plugin-prometheus.config

@@ -0,0 +1,15 @@
+[access]
+	inheritFrom = openstack/meta-config
+
+[access "refs/heads/*"]
+	abandon = group devstack-plugin-prometheus-core
+	label-Code-Review = -2..+2 group devstack-plugin-prometheus-core
+	label-Workflow = -1..+1 group devstack-plugin-prometheus-core
+	toggleWipState = group devstack-plugin-prometheus-core
+
+[receive]
+	requireChangeId = true
+	requireContributorAgreement = true
+
+[submit]
+	mergeContent = true

gerrit/projects.yaml

@@ -3489,6 +3489,10 @@
 - project: openstack/devstack-plugin-pika
   description: RETIRED, DevStack plugin to configure Pika RabbitMQ driver.
   acl-config: /home/gerrit2/acls/openstack/retired.config
+- project: openstack/devstack-plugin-prometheus
+  description: DevStack plugin to install and configure prometheus, node-exporter, pushgateway and alertmanager.
+  groups:
+    - devstack
 - project: openstack/devstack-plugin-zmq
   description: RETIRED, DevStack plugin to configure ZMQ.
   acl-config: /home/gerrit2/acls/openstack/retired.config

gerritbot/channels.yaml

@@ -1060,6 +1060,7 @@ openstack-qa:
     - openstack/devstack-plugin-cookiecutter
     - openstack/devstack-plugin-nfs
     - openstack/devstack-plugin-open-cas
+    - openstack/devstack-plugin-prometheus
     - openstack/devstack-tools
     - openstack/eslint-config-openstack
     - openstack/grenade

zuul/main.yaml

@@ -509,6 +509,7 @@
           - openstack/devstack-plugin-kafka
           - openstack/devstack-plugin-nfs
           - openstack/devstack-plugin-open-cas
+          - openstack/devstack-plugin-prometheus
           - openstack/devstack-tools
           - openstack/devstack-vagrant
           - openstack/diskimage-builder