feat: add iagctl hello-world services

[wcollins]

Description

Ports the hello-torero labs to this repo as IAG hello-world services so users can iagctl db import the manifest and run an Ansible playbook, Python script, and OpenTofu plan against a gateway.

Type of Change

• New feature

Changes Made

• Add import.yml manifest declaring the hello-iagctl repository and three services (hello-ansible, hello-python, hello-opentofu)
• Add hello-ansible/hello-ansible.yml — Ansible debug playbook with two string vars
• Add hello-python/hello-python.py — Python script using argparse for --first_string / --second_string (matches how IAG passes --set key=value)
• Add hello-opentofu/hello-opentofu.tf — OpenTofu plan with two null_resource echoes
• Extend .gitignore with Python (__pycache__, .venv) and OpenTofu (.tofu/, .terraform/, *.tfstate) patterns

README updates land separately.

Testing

iagctl db import --repository https://github.com/itential/hello-itential.git import.yml --validate
iagctl db import --repository https://github.com/itential/hello-itential.git import.yml --check
iagctl db import --repository https://github.com/itential/hello-itential.git import.yml
iagctl get repositories && iagctl get services
iagctl run service ansible-playbook hello-ansible \
  && iagctl run service python-script hello-python \
  && iagctl run service opentofu-plan apply hello-opentofu

Checklist

• Code follows the project's style guidelines
• Self-review of code has been performed
• Commits follow conventional format
• No secrets or credentials committed