Make linuxbox_docker_container envs dynamic

[zimbatm]

Is your feature request related to a problem? Please describe.

Whenever a single env var is being changed, the diff is too large:

# module.consent.linuxbox_docker_container.foo will be updated in-place
  ~ resource "linuxbox_docker_container" "foo" {
      ~ env          = {
          - "AUTH_URL"                 = "http://auth-url/"
          - "DATABASE_URL_API"         = "postgres://user@database_host/db_name"
          - "ENV"                      = "dev"
          - "GCP_BUCKET_ROOT"          = "foo-bar-baz"
          - "RACK_ENV"                 = "production"
          - "RUBYOPT"                  = "-W:deprecated"
          - "SENTRY_URL"               = "https://..."
        } -> (known after apply)
        id           = "74eaa26d18fc146ffd1863bc88f89737094c98cc22b1e9179666cd1b93549664"
      ~ image_id     = "eu.gcr.io/foobar/baz:2283e019" -> "eu.gcr.io/foobar/baz:7bad2e0a"
        name         = "foo"
        # (12 unchanged attributes hidden)
    }

Describe the solution you'd like

Ideally, it would only show the envs that have changed.

And also if the env contains a secret value, not display it.

Describe alternatives you've considered

Additional context