feat(credentials): Add support for revoking group PATs, listing/deleting group SSH keys

This code change adds new functionality to manage SSH keys for enterprise users in GitLab groups. The update introduces three new capabilities: listing all SSH keys associated with users in a group, revoking personal access tokens, and deleting specific SSH keys.

The implementation includes a new data structure to represent SSH key information (like ID, title, creation date, expiration date, and usage details), along with filtering options to search for keys based on creation or expiration dates.

The changes also include comprehensive test coverage to ensure the new features work correctly, including mock implementations for testing purposes. This enhancement allows administrators to better manage security credentials for enterprise users within their GitLab groups, providing more control over access tokens and SSH keys that users can use to authenticate with GitLab services.