docs: Reference kata-ctl README

Add a link to the `kata-ctl` tool's README.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>

README.md

@@ -135,6 +135,7 @@ The table below lists the remaining parts of the project:
 | [kernel](https://www.kernel.org) | kernel | Linux kernel used by the hypervisor to boot the guest image. Patches are stored [here](tools/packaging/kernel). |
 | [osbuilder](tools/osbuilder) | infrastructure | Tool to create "mini O/S" rootfs and initrd images and kernel for the hypervisor. |
 | [`agent-ctl`](src/tools/agent-ctl) | utility | Tool that provides low-level access for testing the agent. |
+| [`kata-ctl`](src/tools/kata-ctl) | utility | Tool that provides advanced commands and debug facilities. |
 | [`trace-forwarder`](src/tools/trace-forwarder) | utility | Agent tracing helper. |
 | [`runk`](src/tools/runk) | utility | Standard OCI container runtime based on the agent. |
 | [`ci`](https://github.com/kata-containers/ci) | CI | Continuous Integration configuration files and scripts. |