migrate Podman to containers/common/libimage

Migrate the Podman code base over to `common/libimage` which replaces
`libpod/image` and a lot of glue code entirely.

Note that I tried to leave bread crumbs for changed tests.

Miscellaneous changes:

 * Some errors yield different messages which required to alter some
   tests.

 * I fixed some pre-existing issues in the code.  Others were marked as
   `//TODO`s to prevent the PR from exploding.

 * The `NamesHistory` of an image is returned as is from the storage.
   Previously, we did some filtering which I think is undesirable.
   Instead we should return the data as stored in the storage.

 * Touched handlers use the ABI interfaces where possible.

 * Local image resolution: previously Podman would match "foo" on
   "myfoo".  This behaviour has been changed and Podman will now
   only match on repository boundaries such that "foo" would match
   "my/foo" but not "myfoo".  I consider the old behaviour to be a
   bug, at the very least an exotic corner case.

 * Futhermore, "foo:none" does *not* resolve to a local image "foo"
   without tag anymore.  It's a hill I am (almost) willing to die on.

 * `image prune` prints the IDs of pruned images.  Previously, in some
   cases, the names were printed instead.  The API clearly states ID,
   so we should stick to it.

 * Compat endpoint image removal with _force_ deletes the entire not
   only the specified tag.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/containers/common/pkg/config/pull_policy.go

@@ -0,0 +1,95 @@
+package config
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+// PullPolicy determines how and which images are being pulled from a container
+// registry (i.e., docker transport only).
+//
+// Supported string values are:
+// * "always"  <-> PullPolicyAlways
+// * "missing" <-> PullPolicyMissing
+// * "newer"  <-> PullPolicyNewer
+// * "never"   <-> PullPolicyNever
+type PullPolicy int
+
+const (
+	// Always pull the image.
+	PullPolicyAlways PullPolicy = iota
+	// Pull the image only if it could not be found in the local containers
+	// storage.
+	PullPolicyMissing
+	// Never pull the image but use the one from the local containers
+	// storage.
+	PullPolicyNever
+	// Pull if the image on the registry is new than the one in the local
+	// containers storage.  An image is considered to be newer when the
+	// digests are different.  Comparing the time stamps is prone to
+	// errors.
+	PullPolicyNewer
+
+	// Ideally this should be the first `ioata` but backwards compatibility
+	// prevents us from changing the values.
+	PullPolicyUnsupported = -1
+)
+
+// String converts a PullPolicy into a string.
+//
+// Supported string values are:
+// * "always"  <-> PullPolicyAlways
+// * "missing" <-> PullPolicyMissing
+// * "newer"   <-> PullPolicyNewer
+// * "never"   <-> PullPolicyNever
+func (p PullPolicy) String() string {
+	switch p {
+	case PullPolicyAlways:
+		return "always"
+	case PullPolicyMissing:
+		return "missing"
+	case PullPolicyNewer:
+		return "newer"
+	case PullPolicyNever:
+		return "never"
+	}
+	return fmt.Sprintf("unrecognized policy %d", p)
+}
+
+// Validate returns if the pull policy is not supported.
+func (p PullPolicy) Validate() error {
+	switch p {
+	case PullPolicyAlways, PullPolicyMissing, PullPolicyNewer, PullPolicyNever:
+		return nil
+	default:
+		return errors.Errorf("unsupported pull policy %d", p)
+	}
+}
+
+// ParsePullPolicy parses the string into a pull policy.
+//
+// Supported string values are:
+// * "always"  <-> PullPolicyAlways
+// * "missing" <-> PullPolicyMissing (also "ifnotpresent" and "")
+// * "newer"   <-> PullPolicyNewer (also "ifnewer")
+// * "never"   <-> PullPolicyNever
+func ParsePullPolicy(s string) (PullPolicy, error) {
+	switch s {
+	case "always":
+		return PullPolicyAlways, nil
+	case "missing", "ifnotpresent", "":
+		return PullPolicyMissing, nil
+	case "newer", "ifnewer":
+		return PullPolicyNewer, nil
+	case "never":
+		return PullPolicyNever, nil
+	default:
+		return PullPolicyUnsupported, errors.Errorf("unsupported pull policy %q", s)
+	}
+}
+
+// Deprecated: please use `ParsePullPolicy` instead.
+func ValidatePullPolicy(s string) (PullPolicy, error) {
+	return ParsePullPolicy(s)
+}