sos: introduce bucket policy resource

[sauterp]

Description

Since the AWS provider isn't compatible anymore with our bucket policy format we introduce our own resource for this purpose.

It was necessary to update github.com/hashicorp/terraform-plugin-testing because it required each resource to have an "id" attribute, which is not actually required by terraform itself, only by this testing library. Thus this requirement was removed in v1.5.0.

Checklist

(For exoscale contributors)

• Changelog updated (under Unreleased block)
• Acceptance tests OK
• For a new resource, datasource or new attributes: acceptance test added/updated

Testing

=== RUN   TestSOSBucketPolicy
--- PASS: TestSOSBucketPolicy (129.50s)
PASS
ok  	github.com/exoscale/terraform-provider-exoscale/pkg/resources/sos_bucket_policy	129.513s

[sauterp]

I'd like to update the govulncheck dependencies in a separate PR. This one already updates some necessary ones and is a quarter of a million lines of code :/