[TIC-958] Signup domain allowlist/blocklist

[itailevi98]

Background

This PR introduces the new env. config fields signup_domain_allowlist_enabled, signup_domain_allowlist, signup_domain_blocklist_enabled, and signup_domain_blocklist.

Logic was smoke-tested with the following resource, with all create, read, and update functionality working as expected:

terraform {
  required_providers {
    propelauth = {
      source = "registry.terraform.io/propelauth/propelauth"
    }
  }
}

provider "propelauth" {
...
}

resource "propelauth_basic_auth_configuration" "example" {
  signup_domain_allowlist         = ["example.com", "a.example.com"]
 # or  signup_domain_blocklist         = ["b.example.com"]
}

[mrmauer]

Mostly lgtm. Just two questions/comments for improved DX:

1. Can we add a validation that we don't get both a allow list and block list? See here for an example of the ValidateConfig interface.
2. Can we just drop the ..._list_enabled attributes and infer these from a list being provided in the plan (and if none provided, then false)?

[itailevi98]

@mrmauer great suggestions :) Updated the basic_auth_configuration_resource to handle the ..._enabled functionality internally, as well as validate that both are not set together

[mrmauer]

The logic all lgtm!
Just a couple little clean-up nits before merging

[mrmauer]

[nit] Can we deleted the commented out code here and below?

[mrmauer]

Can we remove any references in these field docstrings to the now deleted fields such as signup_domain_allowlist_enabled?

[mrmauer]

LGTM!