Update c/image to v4.0.1 and buildah to 1.11.3

This requires updating all import paths throughout, and a matching
buildah update to interoperate.

I can't figure out the reason for go.mod tracking
	github.com/containers/image v3.0.2+incompatible // indirect
((go mod graph) lists it as a direct dependency of libpod, but
(go list -json -m all) lists it as an indirect dependency),
but at least looking at the vendor subdirectory, it doesn't seem
to be actually used in the built binaries.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

vendor/github.com/containers/libtrust/README.md

@@ -0,0 +1,22 @@
+# libtrust
+
+> **WARNING** this library is no longer actively developed, and will be integrated
+> in the [docker/distribution][https://www.github.com/docker/distribution]
+> repository in future.
+
+Libtrust is library for managing authentication and authorization using public key cryptography.
+
+Authentication is handled using the identity attached to the public key.
+Libtrust provides multiple methods to prove possession of the private key associated with an identity.
+ - TLS x509 certificates
+ - Signature verification
+ - Key Challenge
+
+Authorization and access control is managed through a distributed trust graph.
+Trust servers are used as the authorities of the trust graph and allow caching portions of the graph for faster access.
+
+## Copyright and license
+
+Code and documentation copyright 2014 Docker, inc. Code released under the Apache 2.0 license.
+Docs released under Creative commons.
+