Add CI boilerplate

Change-Id: Id8cc08a0951f7347250a2aaa703438e3adfb5e95

.gitreview

@@ -0,0 +1,4 @@
+[gerrit]
+host=review.opendev.org
+port=29418
+project=openstack/charm-cinder-netapp.git

.zuul.yaml

@@ -0,0 +1,5 @@
+- project:
+    templates:
+      - python35-charm-jobs
+      - openstack-python3-ussuri-jobs
+      - openstack-cover-jobs

osci.yaml

@@ -0,0 +1,13 @@
+- project:
+    templates:
+      - charm-unit-jobs
+      - charm-functional-jobs
+    check:
+      jobs:
+        - focal-xena:
+            voting: false
+        - impish-xena:
+            voting: false
+    vars:
+      needs_charm_build: true
+      charm_build_name: cinder-netapp

requirements.txt

@@ -9,6 +9,7 @@
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
 
 # Build requirements
+cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
 charm-tools==2.8.3
 
 simplejson

test-requirements.txt

@@ -5,6 +5,7 @@
 #
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
 
+cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
 stestr>=2.2.0
 
 # Dependency of stestr. Workaround for