Add QoS policy support for object store buckets

[SoulKyu]

Summary

The provider currently does not support attaching a QoS policy to an object store bucket. This is the only granularity at which Pure FlashBlade exposes QoS for S3 workloads, so without provider support
there is no way to enforce per-bucket throttling via Terraform/Pulumi.

Context

The Pure FlashBlade REST API exposes QoS attachment for buckets in two ways:

1. Bucket.qos_policy field — a FixedReference to a QoS policy, settable on bucket create/update.
   Confirmed in pypureclient/flashblade/_common/models/bucket_v_2_22.py:

   qos_policy: Optional[FixedReference] = Field(
       default=None,
       description="The QoS policy for the bucket defines the performance controls that "
                   "can be applied to the aggregate performance of all the clients accessing "
                   "the bucket. If no policy is configured for a bucket, then no performance "
                   "controls are applied to it."
   )

2. QosPolicyMember with member_type=buckets — would mirror the existing file-systems / realms flow.

Current state in the provider

• internal/provider/bucket_resource.go does not expose any qos_policy field.
• qos_policy_member.go (the flashblade_qos_policy_member resource / mica:index:QosPolicyMember) explicitly excludes buckets:

  member_type — "The type of the member. Valid values: file-systems, realms.
  Note: buckets are not supported on API v2.22."
  

Consequence: flashblade_qos_policy can be created against an object store, but cannot be attached to anything S3-related, making the resource effectively a no-op for S3 use cases.

Requested change

Either of (preferred order):

Option A — Add qos_policy to the bucket resource (preferred)

Mirrors the REST API exactly: a single qos_policy (string, name of an existing policy) optional field on flashblade_bucket. Setting it to null/absent means no QoS attached. Updating it triggers a
PATCH on the bucket.

resource "flashblade_bucket" "example" {
  name        = "data-lake"
  account     = "myaccount"
  qos_policy  = flashblade_qos_policy.bucket_throttle.name   # NEW
}

This is the most idiomatic mapping and supports import cleanly.

Option B — Extend QosPolicyMember to accept member_type = buckets

Removes the existing restriction. Less idiomatic (QoS becomes a separately-managed link) but consistent with how file-systems and realms work today.

Either option unblocks the use case; A is cleaner.

Use case

We use this provider via pulumi-mica to manage 300+ projects' S3 footprint. Per-bucket QoS is the standard FinOps lever to prevent noisy-neighbor effects between dev/test workloads sharing a
FlashBlade. Today our Pulumi code creates QoS policies that go nowhere because the link can't be expressed.

Acceptance criteria

• flashblade_bucket accepts a qos_policy field (Option A) or flashblade_qos_policy_member.member_type accepts "buckets" (Option B).
• Acceptance test against a real FlashBlade verifies the policy is attached and detached.
• Documentation updated.

Workaround in the meantime

We are removing the unused flashblade_qos_policy resource creation from our codebase to avoid creating orphan policies on the array.