Registers the released v0.1.0 rancher secrets plugin in the OpenBao plugin
catalog so it can be mounted. The binary is laid down on the vault nodes by
Puppet (openbao-plugin-secrets-rancher RPM).
- Add config/plugins/vault-plugin-secrets-rancher.yaml (type=secret,
command=vault-plugin-secrets-rancher, sha256 pinned to the released binary).
Split plugin catalog registration out of the per-engine backend modules into its own concern (previously bundled into #87's gpg_secret_backend).
## Changes
- New generic `plugin` module (`vault_plugin`: type/name/command/sha256/plugin_version) that imports a binary into the catalog.
- New `config/plugins/` discovery group (filename = catalog name = mount type), wired through `vault_cluster` (`plugins` variable + module) and the syd1 environment.
- `config/plugins/vault-plugin-secrets-gpg.yaml` pins the released v0.1.0 binary sha256 (`0e92d740…a7b20`, from the published RPM). Puppet installs the RPM floating, so bump this in lockstep on upgrade.
Any engine now registers its plugin by dropping a file in `config/plugins/`; its `*_secret_backend` module just mounts the registered type.
Needs the deployer's plugin-catalog access (#88). Merge order: **#88 → this → #87**.
Reviewed-on: #89
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>