backblaze/api-key v0.1.0

Adds two new Terraform modules under a new templates/terraform/backblaze/ provider root.

backblaze/bucket wraps b2_bucket: it names the bucket from name_prefix/name_suffix plus a random 6-character suffix (B2 bucket names are globally unique across every B2 account, like S3, so the random suffix matters here even more than for the Scaleway bucket modules), always creates the bucket as allPrivate (no public-bucket option), and stores an optional description in the bucket's bucket_info metadata. It outputs bucket_id and bucket_name.

backblaze/api-key wraps b2_application_key: it takes a required key_name and a required capabilities set (not validated locally, since Backblaze's capability catalog is provider-defined and changes independently of this repo), an optional bucket_ids set to scope the key to one or more buckets, and defaults valid_duration_in_seconds to 30 days (pass null for a key that never expires). It composes naturally with backblaze/bucket's bucket_id output for per-bucket key scoping, and outputs application_key_id/application_key (sensitive).

See ADR-0147 for the full design rationale. No workloads/* consumer is wired up in this PR — that's left for a future change once a real B2 bucket/key is needed.

This also generalizes template-release.yml's module-discovery find, which was hardcoded to templates/terraform/scaleway and would otherwise have silently skipped tagging/releasing these new modules, and appends both to module-docs.yml's working-dir list so their README input/output tables get generated.

#253