Add helm 'values' flags to create dashboard

[laupse]

What changed?
flags --values added to create dashboard and beta run so we can provide additional helm values when generating HelmRelease from the gitopscli

Why was this change made?
Didn't wanted to have to deal with editing the yaml HelmRelease file to add values

How was this change implemented?
This is has been inspired by how it is implemented in flux for creating HelmRelease

How did you validate the change?
with this yaml

# cat weave-gitops-dashboard.yaml
  service:
    type: nodePort
    nodePort: 30000

we have this export from the below command

# go run cmd/gitops/main.go create dashboard ww-gitops --password=password --export --values="./weave-gitops-dashboard.yaml" | tail -25
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  annotations:
    metadata.weave.works/description: This is the Weave GitOps Dashboard.  It provides
      a simple way to get insights into your GitOps workloads.
  name: ww-gitops
  namespace: flux-system
spec:
  chart:
    spec:
      chart: weave-gitops
      sourceRef:
        kind: HelmRepository
        name: ww-gitops
  interval: 1h0m0s
  values:
    adminUser:
      create: true
      passwordHash: $2a$10$fUEMY4RTq4L6H3t2xkmiAOSGSmjxlOuepzoL.dzTDVTlbTtLWFT0S
      username: admin
    service:
      nodePort: 30000
      type: nodePort

Release notes
N/A

Documentation Changes
cli is self documented

[laupse]

Hi, sorry i drop this PR from nowhere. I was playing with the gitops cli to create helm flux manifest for the dashboard. And i wanted to add some configuration for the weave dashboard k8s service. I try first to do just like,i would do with flux create helmrelease --values... but there was no equivalent in the gitops cli. So i took a little time to implement.
Hope you find this useful, let me know 😄

[yiannistri]

@laupse thank you for sending this PR, the new CLI flag is a useful addition 👍

I took the liberty of editing your PR slightly and I have now asked for another review. But I think it should be good to merge soon.

[yitsushi]

lgtm

[laupse]

Thank you for taking time considering and merging this PR 😄