feat: RunnerDeployment

Adds the initial version of RunnerDeployment that is intended to manage RunnerSets(#1), like Deployment manages ReplicaSets.

This is the initial version and therefore is bare bone. The only update strategy it supports is `Recreate`, which recreates the underlying RunnerSet when the runner template changes. I'd like to add `RollingUpdate` strategy once this is merged.

This depends on #1 so the diff contains that of #1, too. Please see only the latest commit for review.

Also see https://github.com/mumoshu/actions-runner-controller-ci/runs/471329823?check_suite_focus=true to confirm that `make tests` is passing after changes made in this commit.

config/rbac/role.yaml

@@ -6,6 +6,26 @@ metadata:
   creationTimestamp: null
   name: manager-role
 rules:
+- apiGroups:
+  - actions.summerwind.dev
+  resources:
+  - runnerdeployments
+  verbs:
+  - create
+  - delete
+  - get
+  - list
+  - patch
+  - update
+  - watch
+- apiGroups:
+  - actions.summerwind.dev
+  resources:
+  - runnerdeployments/status
+  verbs:
+  - get
+  - patch
+  - update
 - apiGroups:
   - actions.summerwind.dev
   resources: