Add a new `enable_criu` configuration option under CRI plugin runtime
settings. When set to false, any checkpoint or restore request will fail
fast with an error indicating that CRIU support is disabled by
configuration. `enable_criu` currently defaults to true.
Add an integration test script to verify that setting `enable_criu` to
false in containerd configuration successfully disables checkpoint and
restore operations and fails fast.
Assisted-by: Antigravity
Signed-off-by: Samuel Karp <samuelkarp@google.com>