chore: update tflint job to be compatible with v0.40.0+ config model

No breaking changes. This change preserves old behaviour by creating simple .tflint.hcl file with

plugin "terraform" {
  enabled = true
  preset  = "all"
}

Preset "all" means these rules are enabled, so we can drop this long command with endless `--enable-rule`.

If file already exists, the tflint will use it.

part of https://gitlab.developers.cam.ac.uk/uis/devops/gcp-deploy-boilerplate/-/issues/52