feat(container_registry): add container_registry resource and data source

[seiji]

Summary

Add crowdstrike_container_registry resource and crowdstrike_container_registry data source for managing container registry connections in CrowdStrike Falcon Container Security.

Closes #312

What's included

• crowdstrike_container_registry resource — full CRUD lifecycle with import support
• crowdstrike_container_registry data source — look up a registry by ID

Design decisions

• 17 registry types: Supports acr, artifactory, docker, dockerhub, ecr, gar, gcr, github, gitlab, harbor, icr, mirantis, nexus, openshift, oracle, quay.io with type-specific credential validation via ValidateConfig
• Credential as attribute: credential is defined as SingleNestedAttribute (not a block) to allow Required constraint and null/unknown handling
• Create API workaround: The Create API returns HTTP 200 instead of the expected 201, which gofalcon treats as an error. Falls back to findRegistryByURL (URL + type + user_defined_alias matching) to locate the created entity
• Write-only credential fields: Credential input fields (username, password, etc.) are not returned by the API. They are preserved in state from the plan and excluded from import verification via ImportStateVerifyIgnore
• url_uniqueness_key: Sent on Create only; not returned by the API and therefore not usable for matching. Kept in schema for API compatibility but marked RequiresReplace

Testing

• TestAccContainerRegistryResource_DockerHub — Create, update credential, import
• TestAccContainerRegistryDataSource_basic — Read by ID (requires TEST_CONTAINER_REGISTRY_ID)
• Verified against a live CrowdStrike tenant (us-2)

Checklist

• go build passes
• golangci-lint — 0 issues
• make gen — documentation generated and committed
• Acceptance tests pass
• Example configurations and import scripts included
• Sweeper implemented for test cleanup
• Resource and data source registered in provider

[seiji]

Fixed the lint errors. 1851a4c
https://github.com/CrowdStrike/terraform-provider-crowdstrike/actions/runs/24997404320/job/73588238151

Could you take another look when you have a chance?

[seiji]

This PR was not necessarily intended to request a merge, but rather to highlight the operational need for this functionality.

I would appreciate it if you could consider this capability for future product implementation or roadmap discussions.