feat: add mysql chart (#5)

I ran the following to pull the bitnami mysql chart and index it. I plan
to use this instead of the mariadb chart as we are upgrading to mysql 8.

```
helm pull oci://registry-1.docker.io/bitnamicharts/mysql
./scripts/update-index.sh
```

The mariadb version is indexed with a different version suffixed by
`-subpath`. I reverted those changes to the index file to avoid breaking
changes as they appear to be custom.

QSS-2315

index.yaml

@@ -25,6 +25,47 @@ entries:
     urls:
     - https://getoutreach.github.io/helm-charts-public/mariadb-0.3.0.tgz
     version: 0.3.0
+  mysql:
+  - annotations:
+      category: Database
+      images: |
+        - name: mysql
+          image: docker.io/bitnami/mysql:8.0.36-debian-11-r4
+        - name: mysqld-exporter
+          image: docker.io/bitnami/mysqld-exporter:0.15.1-debian-11-r5
+        - name: os-shell
+          image: docker.io/bitnami/os-shell:11-debian-11-r96
+      licenses: Apache-2.0
+    apiVersion: v2
+    appVersion: 8.0.36
+    created: "2024-02-09T15:07:56.969910632-08:00"
+    dependencies:
+    - name: common
+      repository: oci://registry-1.docker.io/bitnamicharts
+      tags:
+      - bitnami-common
+      version: 2.x.x
+    description: MySQL is a fast, reliable, scalable, and easy to use open source
+      relational database system. Designed to handle mission-critical, heavy-load
+      production applications.
+    digest: ce316b83566b786e355bb264fb8cdceb864aae2816f583ae2c22275a7f5ddcd9
+    home: https://bitnami.com
+    icon: https://bitnami.com/assets/stacks/mysql/img/mysql-stack-220x234.png
+    keywords:
+    - mysql
+    - database
+    - sql
+    - cluster
+    - high availability
+    maintainers:
+    - name: VMware, Inc.
+      url: https://github.com/bitnami/charts
+    name: mysql
+    sources:
+    - https://github.com/bitnami/charts/tree/main/bitnami/mysql
+    urls:
+    - https://getoutreach.github.io/helm-charts-public/mysql-9.19.1.tgz
+    version: 9.19.1
   rabbitmq:
   - apiVersion: v2
     appVersion: 3.8.18
@@ -38,4 +79,4 @@ entries:
     urls:
     - https://getoutreach.github.io/helm-charts-public/rabbitmq-0.3.1.tgz
     version: 0.3.1
-generated: "2023-05-23T08:15:36.207548-07:00"
+generated: "2024-02-09T15:07:56.963960107-08:00"