rename gitea readme in accordance with standard

kubernetes/graduated/gitea/gitea.md

@@ -5,6 +5,8 @@
   - [Install](#install)
   - [Backup and Restore](#backup-and-restore)
   - [Gitea Runners](#gitea-runners)
+    - [Install](#install-1)
+    - [Cache Cleanup](#cache-cleanup)
 
 Gitea provides a helm chart [here](https://gitea.com/gitea/helm-chart/). We're not
 going to modify much, but we are going to solidify some of the default values in case
@@ -78,6 +80,8 @@ kubectl scale statefulset gitea --replicas 1
 
 <https://docs.gitea.com/next/usage/actions/act-runner/#install-with-the-docker-image>
 
+### Install
+
 ```bash
 touch config.yaml
 
@@ -95,3 +99,30 @@ docker run \
     --name kube_runner \
     -d gitea/act_runner:latest
 ```
+
+### Cache Cleanup
+
+Each org or project with a package registry will have its own cleanup rules. For example,
+services -> settings -> Packages -> Add Cleanup Rule will allow you to create a cleanup
+rule for packages stored under the "services" org. These cleanup rules should run automatically.
+
+On the other hand, the docker builder cache will balloon out of control over time. The gitea
+docker runner is handled outside of Gitea's context, so you'll need to clean it up yourself.
+
+```bash
+# Check used system resources
+docker system df
+```
+
+You should run something like this on a schedule:
+
+```bash
+# Prune the builder cache
+docker builder prune -a
+```
+
+To run it every day at midnight: `crontab -e`
+
+```bash
+0 0 * * * yes | docker builder prune -a
+```