Allow to override VAULT_CLUSTER_ADDR and VAULT_ADDR

**Is your feature request related to a problem? Please describe.**
Right now those values are set to the internal pod dns, e.g.. `https://vault-0.vault-internal:8201`. While this works, I am trying to set up Vault over multiple clusters, using internal loadbalancer.

I tried to set the value in the config:

```
config: |
ui = true
api_addr = ":8200"
cluster_addr = ":8200"
```

But it seems this is being overridden by the environment variable:

==> Vault server configuration:
GCP KMS Crypto Key: <>
GCP KMS Key Ring: <>
GCP KMS Project: <>
GCP KMS Region: global
Seal Type: gcpckms
Api Address: http://:8200
Cgo: disabled
Cluster Address: https://vault-0.vault-internal:8201
Listener 1: tcp (addr: "[::]:8200", cluster address: "[::]:8201", max_reques
t_duration: "1m30s", max_request_size: "33554432", tls: "disabled")
Log Level: info
Mlock: supported: true, enabled: false
Recovery Mode: false
Storage: gcs (HA available)
Version: Vault v1.4.2

**Describe the solution you'd like**
Allow to override those values using `values.yaml`, e.g. by setting `server.clusterAddress` and `sever.address`, or even to disable the env var, so the config will be applied.