Include an example for enabling the admin user on an akp_instance

[morey-tech]

The docs should Include a clear example for enabling the admin user using the akp_instance resource. I see this as a common use case. It should include the changes to the argocd_cm, argocd_secret, and how to generate a bcrypt password to use in the secret. Something like:

resource "akp_instance" "argocd" {
  ...
  argocd_cm = {
    # When configuring the `argocd_cm`, make sure to specify the following keys 
    # (from "admin.enabled", to "users.anonymous.enabled") since those keys are
    # added by Akuity Platform by default. If they are not defined, you may see
    # inconsistent results and errors from the provider. Feel free to customize
    # the values based on your usage, but the keys themselves must be specified.
    # Note that "admin.enabled" cannot be set to true independently, and an
    # "accounts.admin" key is required, like the "accounts.alice" key below, once
    # you add that, remove the "admin.enabled" key.
    "admin.enabled"                  = true
    "exec.enabled"                   = false
    "ga.anonymizeusers"              = false
    "helm.enabled"                   = true
    "kustomize.enabled"              = true
    "server.rbac.log.enforce.enable" = false
    "statusbadge.enabled"            = false
    "ui.bannerpermanent"             = false
    "users.anonymous.enabled"        = false

    "accounts.admin"     = "login"
  }
  argocd_secret = {
    # Generated with `argocd account bcrypt --password my-password`.
    "admin.password" = "$2a$10$JN8tnDT48oz409O/yTYqjeDKsHY7dOx.pzEwPpamP/UEl.l9KfszO%"
  }