docs: add Trivy scan badges

| Input / Variable | Description                            | Default value     |

| ------------------------ | -------------------------------------- | ----------------- |

| `cli-image` / `AZURE_CLI_IMAGE` | the Docker image used to run Azure CLI commands| `mcr.microsoft.com/azure-cli:latest` |

| `cli-image` / `AZURE_CLI_IMAGE` | the Docker image used to run Azure CLI commands| `mcr.microsoft.com/azure-cli:latest` <br/>[![Trivy Badge](https://to-be-continuous.gitlab.io/doc/secu/trivy-badge-AZURE_CLI_IMAGE.svg)](https://to-be-continuous.gitlab.io/doc/secu/trivy-AZURE_CLI_IMAGE) |

| `base-app-name` / `AZURE_BASE_APP_NAME` | Base application name                  | `$CI_PROJECT_NAME` ([see GitLab doc](https://docs.gitlab.com/ee/ci/variables/predefined_variables.html)) |

| `environment-url` / `AZURE_ENVIRONMENT_URL`  | Default environments url _(only define for static environment URLs declaration)_<br/>_supports late variable expansion (ex: `https://%{environment_name}.azure.acme.com`)_ | _none_ |

| `scripts-dir` / `AZURE_SCRIPTS_DIR` | Directory where Azure scripts (deploy & cleanup) are located | `.` _(root project dir)_ |