[COR-166] Generate password and create secret

[ianstanton]

Generate password for user postgres and store it in a kubernetes secret. This secret also contains connection info such as host, port, user, and uri. Example:

❯ k get secret sample-coredb-connection -o yaml
apiVersion: v1
data:
  host: c2FtcGxlLWNvcmVkYi1jb25uZWN0aW9uLmRlZmF1bHQuc3ZjLmNsdXN0ZXIubG9jYWw=
  password: eXI5eGE3UjU=
  port: NTQzMg==
  uri: cG9zdGdyZXNxbDovL3Bvc3RncmVzOnlyOXhhN1I1QHNhbXBsZS1jb3JlZGItY29ubmVjdGlvbi5kZWZhdWx0LnN2Yy5jbHVzdGVyLmxvY2FsOjU0MzI=
  user: cG9zdGdyZXM=
kind: Secret
metadata:
  creationTimestamp: "2023-01-26T15:49:25Z"
  labels:
    app: coredb
  name: sample-coredb-connection
  namespace: default
  ownerReferences:
  - apiVersion: coredb.io/v1alpha1
    controller: true
    kind: CoreDB
    name: sample-coredb
    uid: cbedc5c2-12a0-48f2-a7dd-8dcb35e8b531
  resourceVersion: "57082"
  uid: a3941387-5207-4008-b969-d0b3623a00c7
type: Opaque

[ianstanton]

Opening up for review while I fix tests

[sjmiller609]

just one nit pick