system df: fix image-size calculations

Fix two bugs in `system df`:

1.  The total size was calculated incorrectly as it was creating the sum
    of all image sizes but did not consider that a) the same image may
    be listed more than once (i.e., for each repo-tag pair), and that
    b) images share layers.

    The total size is now calculated directly in `libimage` by taking
    multi-layer use into account.

2.  The reclaimable size was calculated incorrectly.  This number
    indicates which data we can actually remove which means the total
    size minus what containers use (i.e., the "unique" size of the image
    in use by containers).

NOTE: The c/storage version is pinned back to the previous commit as it
      is buggy.  c/common already requires the buggy version, so use a
      `replace` to force/pin.

Fixes: #16135
Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

vendor/github.com/containers/common/pkg/report/doc.go

@@ -4,6 +4,7 @@ Package report provides helper structs/methods/funcs for formatting output
 To format output for an array of structs:
 
 ExamplePodman:
+
 	headers := report.Headers(struct {
 		ID string
 	}{}, nil)
@@ -24,6 +25,7 @@ ExamplePodman:
 	// fa85da03b40141899f3af3de6d27852b
 
 ExampleUser:
+
 	headers := report.Headers(struct {
 		CID string
 	}{}, map[string]string{"CID":"ID"})
@@ -55,19 +57,18 @@ Helpers:
 Template Functions:
 
 The following template functions are added to the template when parsed:
-	- join  strings.Join, {{join .Field separator}}
-	- json encode field as JSON {{ json .Field }}
-	- lower strings.ToLower {{ .Field | lower }}
-	- pad add spaces as prefix and suffix {{ pad . 2 2 }}
-	- split strings.Split {{ .Field | split }}
-	- title strings.Title {{ .Field | title }}
-	- truncate limit field length {{ truncate . 10 }}
-	- upper strings.ToUpper {{ .Field | upper }}
+  - join  strings.Join, {{join .Field separator}}
+  - json encode field as JSON {{ json .Field }}
+  - lower strings.ToLower {{ .Field | lower }}
+  - pad add spaces as prefix and suffix {{ pad . 2 2 }}
+  - split strings.Split {{ .Field | split }}
+  - title strings.Title {{ .Field | title }}
+  - truncate limit field length {{ truncate . 10 }}
+  - upper strings.ToUpper {{ .Field | upper }}
 
 report.Funcs() may be used to add additional template functions.
 Adding an existing function will replace that function for the life of that template.
 
-
 Note: Your code should not ignore errors
 */
 package report