Remove HDInsightContainers SDK due to HDInsightOnAKS deprecation

[2258093686]

HDInsightOnAKS service was retired on January 31, 2025; so the SDK for it is now useless and can be removed.
Retirement Announcement: https://azure.microsoft.com/en-us/updates?id=azure-hdinsight-on-aks-retirement

[Copilot]

Pull Request Overview

This pull request removes the entire armhdinsightcontainers SDK module by deleting all of its source files, including:

• Core client implementations (operations, locations, clusters, cluster pools)
• Model serialization code (models_serde.go with 5682 lines)
• Type definitions (responses.go, options.go, interfaces.go)
• Helper utilities (time_rfc3339.go, polymorphic_helpers.go)
• Fake/test server implementations
• Module dependencies (go.mod, go.sum)
• Example test files

Key Changes

• Complete removal of the HDInsight Containers ARM SDK module
• Deletion of ~7500+ lines of generated code
• Removal of all client implementations, models, and supporting infrastructure
• Elimination of module dependencies and test infrastructure

Reviewed Changes

Copilot reviewed 54 out of 56 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
go.mod, go.sum	Removed module dependencies and version constraints
models_serde.go	Deleted 5682 lines of model serialization/deserialization code
operations_client.go, locations_client.go	Removed API client implementations
responses.go, options.go	Deleted type definitions for API responses and options
time_rfc3339.go	Removed RFC3339 time handling utilities
polymorphic_helpers.go	Deleted polymorphic type unmarshaling helpers
interfaces.go	Removed interface definitions for polymorphic types
fake/*.go	Deleted all fake server implementations for testing
*_example_test.go	Removed example test files

[2258093686]

The Azure SDK has been marked as deprecated.
Azure/azure-sdk#9363