Better instructions for Sentinel with terraform.

## Add these notes in website to help new sentinel beginners
#### Its like "a quickstart guide to use sentinel with terraform"
---

Example (sentinel.hcl) file for terraform:
```
sentinel {
features = {
apply-all = true
terraform = true
}
}

import "plugin" "tfplan/v2" {
config = {
"plan_path": "./tfplan.json"
}
}
```
Example rule for terraform version parser:
```
import "tfplan/v2" as tfplan
import "strings"

v = strings.split(tfplan.terraform_version, ".")

version_major = int(v[0])
version_minor = int(v[1])

print(version_major,version_minor)
```
**Notes**:
- In root folder you should have a file named `sentinel.hcl`. This is used for settings (e.g import plugins like 'tfplan' ).
- tfplan shall have exact path of plan file in config.

---

**Quick steps to run with terraform**
1. `terraform plan -out=tfplan` --> export of plan file
2. `terraform show -json tfplan > tfplan.json` --> export plan in json
3. edit `sentinel.hcl` `plan_path` to match `./tfplan.json` (exact path)
4. finally run sentinel to test configuration with `sentinel apply -trace -config `
---

### Hope these instructions will be imported in website of documentation to help newcomers
### Your instructions are not clear in many places.

Start by locating the website documentation and any existing Sentinel or Terraform guides. Add a quickstart covering the sentinel.hcl example, Terraform plan-to-JSON steps, plan_path configuration, and the sentinel apply command. Done means a newcomer can follow the guide to test a Terraform configuration.

Written by the indexing model from the issue text.