Remove IAM user alexe

[ale210]

Part of #212 (end-to-end test, step 1 of 2: remove alexe; a follow-up PR recreates the account as ale210, named after the GitHub handle, with a slack_id so the user-bot DMs it a temporary password)

What changes did you make?

• Removed the iam_user_alexe module block from terraform/aws-users.tf

Why did you make the changes (we will use this info to test)?

• The account is being recreated under the GitHub handle ale210, as the naming convention expects, and the new user's CreateLoginProfile is the end-to-end test for the user-bot
• Expected plan: 0 to add, 0 to change, 3 to destroy: the user, its login profile and its ops-leads membership
• force_destroy also deletes the user's access key and a directly attached IAMUserChangePassword policy that was never in Terraform. Both are intended

[github-actions]

Terraform plan in terraform
With backend config files: terraform/prod.backend.tfvars
With variables: iam_only = false

Plan: 0 to add, 0 to change, 3 to destroy.

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
-   destroy

Terraform will perform the following actions:

  # module.iam_user_alexe.aws_iam_user.user will be destroyed
  # (because aws_iam_user.user is not in configuration)
-   resource "aws_iam_user" "user" {
-       arn                  = "arn:aws:iam::035866691871:user/alexe" -> null
-       force_destroy        = true -> null
-       id                   = "alexe" -> null
-       name                 = "alexe" -> null
-       path                 = "/" -> null
-       tags                 = {
-           "Access Level" = "1"
-           "Project"      = "devops-security"
        } -> null
-       tags_all             = {
-           "Access Level" = "1"
-           "Project"      = "devops-security"
-           "managed-by"   = "terraform-devops-security"
        } -> null
-       unique_id            = "AIDAQQWOSJEPUDCMYCMNE" -> null
#        (1 unchanged attribute hidden)
    }

  # module.iam_user_alexe.aws_iam_user_group_membership.user_group_membership will be destroyed
  # (because aws_iam_user_group_membership.user_group_membership is not in configuration)
-   resource "aws_iam_user_group_membership" "user_group_membership" {
-       groups = [
-           "ops-leads",
        ] -> null
-       id     = "terraform-20240815021728326500000001" -> null
-       user   = "alexe" -> null
    }

  # module.iam_user_alexe.aws_iam_user_login_profile.user_login will be destroyed
  # (because aws_iam_user_login_profile.user_login is not in configuration)
-   resource "aws_iam_user_login_profile" "user_login" {
-       id                      = "alexe" -> null
-       password                = (sensitive value) -> null
-       password_length         = 20 -> null
-       password_reset_required = false -> null
-       user                    = "alexe" -> null
    }

Plan: 0 to add, 0 to change, 3 to destroy.

✅ Plan applied in Apply Terraform changes on merge #52