fix: use postgres 16 containers for db (#4391)

### Description

Use the postgres 16 containers

> NOTE:

### Checklist

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- [ ]
[CHANGELOG.md](https://github.com/sourcegraph/sourcegraph/blob/main/CHANGELOG.md)
updated
- [ ] [K8s Upgrade notes
updated](https://github.com/sourcegraph/sourcegraph/blob/main/doc/admin/updates/kubernetes.md)
- [x] Sister
[deploy-sourcegraph-k8s](https://github.com/sourcegraph/deploy-sourcegraph-docker)
change:
- [x] Sister
[deploy-sourcegraph-docker](https://github.com/sourcegraph/deploy-sourcegraph-docker)
change:
- [x] All images have a valid tag and SHA256 sum
- [x] I acknowledge that
[deploy-sourcegraph-k8s](https://github.com/sourcegraph/deploy-sourcegraph-k8s)
is now the preferred Kubernetes deployment repository

### Test plan
CI
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base/codeinsights-db/codeinsights-db.Deployment.yaml

@@ -42,7 +42,7 @@ spec:
             memory: "50Mi"
       containers:
       - name: codeinsights
-        image: index.docker.io/sourcegraph/codeinsights-db:5.9.1590@sha256:4e75b2c463ce1ef3bfeec4bb71a16693df02005e66b9e697859ce61064e08f42
+        image: index.docker.io/sourcegraph/postgresql-16-codeinsights:insiders
         env:
         - name: POSTGRES_DB
           value: postgres

base/codeintel-db/codeintel-db.Deployment.yaml

@@ -43,7 +43,7 @@ spec:
             memory: "50Mi"
       containers:
       - name: pgsql
-        image: index.docker.io/sourcegraph/codeintel-db:5.9.1590@sha256:3d5dd36e3af6b643903f507422be19ed1cb1f5f71c4541572d4a8a252e81aeb8
+        image: index.docker.io/sourcegraph/postgresql-16:insiders
         terminationMessagePolicy: FallbackToLogsOnError
         readinessProbe:
           exec:

base/pgsql/pgsql.Deployment.yaml

@@ -43,7 +43,7 @@ spec:
             memory: "50Mi"
       containers:
       - env:
-        image: index.docker.io/sourcegraph/postgres-12-alpine:5.9.1590@sha256:3d5dd36e3af6b643903f507422be19ed1cb1f5f71c4541572d4a8a252e81aeb8
+        image: index.docker.io/sourcegraph/postgresql-16:insiders
         terminationMessagePolicy: FallbackToLogsOnError
         readinessProbe:
           exec: