Describe the feature or problem you’d like to solve

Add support for managing users SSH key related operations:

List users' SSH keys
Get details about a user's SSH key
Add a public key

Proposed solution

How will it benefit GitHub MCP Server and its users?

Adding these features will benefit the GitHub MCP Server and its users by allowing them to manage and debug issues related to SSH keys associated with their GitHub account.

Users will be able to effectively manage their SSH keys which can help in resolving frequent permission denied errors encountered during git operations (pull/push etc).

Additional context

The motivation behind adding these tools is to ensure users have their SSH keys correctly configured, as we receive numerous requests concerning permission denied messages.