chore: set git clone & dotfiles as optional

[ericpaulsen]

customers are making good use of our dotfiles & git clone modules. however, there are scenarios where users may not want to set a repo URL or dotfiles URL, despite the module being present in the template.

the changes in this PR prevent the modules from failing if such fields are unset.

[phorcys420]

Hey @ericpaulsen, my opinion is that the count attribute of the module should be set based on a coder_parameter value for this kind of use-case, do you think this would be possible?

[ericpaulsen]

@phorcys420 yes, could you give me a code snippet of what you are describing?

[phorcys420]

I was convinced that something like this would work:

data "coder_parameter" "enable_code_server" {
  name    = "code-server?"
  type    = "bool"
  default = true
}

module "code-server" {
  count                   = data.coder_parameter.enable_code_server.value == true ? 1 : 0
  source                  = "dev.registry.coder.com/modules/code-server/coder"
  version                 = ">= 1.0.0"
  agent_id                = coder_agent.dev.id
  folder                  = local.repo_dir
  auto_install_extensions = true
}

But I couldn't get it to ever add the module, maybe it doesn't work with modules.
@matifali do you have an idea?

[phorcys420]

@ericpaulsen that said, I don't think we should make the script more permissive for an edge-case, rather add a do-nothing toggle if using count doesn't work.

[matifali]

We should handle this in the terraform and make the input optional and skip running the coder_script.
I can take a detailed look tomorrow morning.

[phorcys420]

@matifali were you able to take a look? otherwise i can take it from now on

[matifali]

@phorcys420 no I wasn't. It would be nice if you can. Thanks 🙏

[matifali]

We are moving to https://github.com/coder/regitsry. Please move your PR there. Thanks
More context in #469