S3: Enforce bucket policy (#7471)

* evaluate policies during authorization

* cache bucket policy

* refactor

* matching with regex special characters

* Case Sensitivity, pattern cache, Dead Code Removal

* Fixed Typo, Restored []string Case, Added Cache Size Limit

* hook up with policy engine

* remove old implementation

* action mapping

* validate

* if not specified, fall through to IAM checks

* fmt

* Fail-close on policy evaluation errors

* Explicit `Allow` bypasses IAM checks

* fix error message

* arn:seaweed => arn:aws

* remove legacy support

* fix tests

* Clean up bucket policy after this test

* fix for tests

* address comments

* security fixes

* fix tests

* temp comment out

test/s3/iam/STS_DISTRIBUTED.md

@@ -248,7 +248,7 @@ services:
 3. User calls SeaweedFS STS AssumeRoleWithWebIdentity
    POST /sts/assume-role-with-web-identity
    {
-     "RoleArn": "arn:seaweed:iam::role/S3AdminRole",
+     "RoleArn": "arn:aws:iam::role/S3AdminRole",
      "WebIdentityToken": "eyJ0eXAiOiJKV1QiLCJhbGc...",
      "RoleSessionName": "user-session"
    }