Integration request: packer-plugin-image-builder

#### Description

HashiCorp [Packer](https://www.packer.io/) plugin for [image-builder-cli](https://github.com/osbuild/image-builder-cli) and [bootc-image-builder](https://github.com/osbuild/bootc-image-builder). Builds are done on a remote linux machine over SSH.

The plugins is available at: https://github.com/osbuild/packer-plugin-image-builder

#### Integration Tier

This plugin is maintained by osbuild community which is backed by [Red Hat](https://www.hashicorp.com/en/partners/tech/red-hat). The osbuild tool, also known as image-builder, is shipped in Red Hat Enterprise Linux. The osbuild GH org is controlled by Red Hat employees and meets the company security standards (2FA). Both mentioned tools are currently upstream-only emerging tech that will be eventually integrated into Fedora and Red Hat Enterprise Linux. Therefore, community integration tier is fine.

#### Checklist
- [x] Has valid [`metadata.hcl`](https://github.com/hashicorp/integration-template) file in plugin repository.
- [ ] Has added integration scripts [packer-plugin-scaffolding](https://github.com/hashicorp/packer-plugin-scoffolding) to plugin repository. - **the link is invalid**
- [ ] Has added top-level integration README.md file to plugin `docs` directory. - **docs are not generated**
- [x] All plugins components have one README.md describing their usage.
- [x] Has a fully synced `.web-docs` directory ready for publishing to the integrations portal.

I am shooting in the dark here, but since the plugin is so simple, we would like to maintain [the plugin documentation](https://github.com/osbuild/packer-plugin-image-builder/tree/main/.web-docs) manually, thus there is no `docs/` folder and no generation of `.web-docs/` is going on at the moment. I hope this is fine and it will work, let me know otherwise and we can change it.

Start by reviewing the integration checklist in this issue and the linked packer-plugin-image-builder repository, especially its metadata.hcl and .web-docs directory. Check the referenced scaffolding and documentation requirements, then confirm with the Packer maintainers what remains before considering the integration complete.

Written by the indexing model from the issue text.