Add devstack-plugin-mariadb as new project

This devstack plugin allow ubuntu users to use the open source forked
version/flavor of mysql, MariaDB, as an alternative to the default
MySQL.

Plugins used in the gate must live in OpenStack's gerrit. Following the
best practices to eventually add experimental/periodic jobs for MariaDB
- e.g: dsvm-tempest-full-mariadb.

Change-Id: I9a5f1fd23b7c4ea2711b9e919149083d29e9af1b

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

@@ -0,0 +1,14 @@
+[access "refs/heads/*"]
+abandon = group devstack-plugin-mariadb-core
+label-Code-Review = -2..+2 group devstack-plugin-mariadb-core
+label-Workflow = -1..+1 group devstack-plugin-mariadb-core
+
+[access "refs/tags/*"]
+pushSignedTag = group devstack-plugin-mariadb-release
+
+[receive]
+requireChangeId = true
+requireContributorAgreement = true
+
+[submit]
+mergeContent = true

gerrit/projects.yaml

@@ -1323,6 +1323,10 @@
   acl-config: /home/gerrit2/acls/openstack/oslo.messaging.config
   groups:
     - oslo
+- project: openstack/devstack-plugin-mariadb
+  description: A DevStack plugin that allows ubuntu users to use MariaDB flavor as the
+    database backend
+  upstream: https://github.com/rafaelfolco/devstack-plugin-mariadb
 - project: openstack/devstack-plugin-nfs
   description: DevStack plugin to configure NFS backend.
 - project: openstack/devstack-plugin-pika

jenkins/jobs/projects.yaml

@@ -1433,6 +1433,12 @@
           plugin-repo: openstack/devstack-plugin-kafka
           job-suffix: ''
 
+- project:
+    name: devstack-plugin-mariadb
+
+    jobs:
+      - gate-{name}-bashate
+
 - project:
     name: devstack-plugin-nfs
     jobs:

zuul/layout.yaml

@@ -5552,6 +5552,14 @@ projects:
       - gate-devstack-plugin-kafka-bashate
       - gate-tempest-dsvm-full-kafka
 
+  - name: openstack/devstack-plugin-mariadb
+    template:
+      - name: merge-check
+    check:
+      - gate-devstack-plugin-mariadb-bashate
+    gate:
+      - gate-devstack-plugin-mariadb-bashate
+
   - name: openstack/devstack-plugin-nfs
     template:
       - name: merge-check