Extend Account to support token and user/password auth

[vavsab]

Also moved repeated parts into shared controller to avoid code duplication.

Why not env var injection like initially proposed?

Injecting as env vars into server URL will leak secrets in logs. To avoid this we need to pass sensitive params into nats client as separate options.

Related to

nats-io/k8s#876
#76

Usage example (token)

apiVersion: v1
kind: Secret
metadata:
  name: nats-token
type: Opaque
data:
  # token. required to be in base64 in Secret.
  token: dG9rZW4=
---
apiVersion: jetstream.nats.io/v1beta2
kind: Account
metadata:
  name: token-acc
spec:
  name: TOKEN_ACCOUNT
  servers:
    - 'nats://localhost:4222'
  token:
    secret:
      name: nats-token
    token: token
---
apiVersion: jetstream.nats.io/v1beta2
kind: Stream
metadata:
  name: js-token
spec:
  account: token-acc
  name: js-token
  storage: file
  subjects:
    - data.>

Usage example (user with password)

apiVersion: v1
kind: Secret
metadata:
  name: nats-user-with-pass
type: Opaque
data:
  # admin/admin. required to be in base64 in Secret.
  user: YWRtaW4=
  password: YWRtaW4=
---
apiVersion: jetstream.nats.io/v1beta2
kind: Account
metadata:
  name: user-pass-acc
spec:
  name: USER_PASS_ACCOUNT
  servers:
    - 'nats://localhost:4222'
  userWithPassword:
    secret:
      name: nats-user-with-pass
    user: user
    password: password
---
apiVersion: jetstream.nats.io/v1beta2
kind: Stream
metadata:
  name: js-user-pass
spec:
  account: user-pass-acc
  name: js-user-pass
  storage: file
  subjects:
    - data.>

[vavsab]

@samuelattwood @adriandieter @ramonberrutti @Jarema @johnweldon @vsinger
Could you please review and merge it?

UPD: I will really appreciate if you create a release as well so I could get rid of using a forked docker image.

[Jarema]

We will take a look at this one shortly.