feat: add fire-client and fire-server crates for MicroVM management
- Created `fire-client` crate with dependencies on `anyhow` and `reqwest`.
- Created `fire-server` crate with dependencies on `actix-web`, `utoipa`, and others for API documentation and handling.
- Implemented MicroVM API endpoints in `fire-server` for creating, deleting, retrieving, listing, starting, and stopping MicroVMs.
- Added SSH keys support in `fire-config` for MicroVM configuration.
- Integrated `fire-server` into the main application with a new `serve` command.
- Updated `firecracker-up` to include `fire-client` and `fire-server` dependencies and added command-line options for SSH keys.