crane/gcrane: add pages (#13853)

pages/common/gcrane-copy.md

@@ -0,0 +1,20 @@
+# gcrane copy
+
+> Efficiently copy a remote image from source to target while retaining the digest value.
+> More information: <https://github.com/google/go-containerregistry/blob/main/cmd/gcrane/README.md>.
+
+- Copy an image from source to target:
+
+`gcrane {{cp|copy}} {{source}} {{target}}`
+
+- Set the maximum number of concurrent copies, defaults to 20:
+
+`gcrane copy {{source}} {{target}} {{-j|--jobs}} {{nr_of_copies}}`
+
+- Whether to recurse through repositories:
+
+`grance copy {{source}} {{target}} {{-r|--recursive}}`
+
+- Display help:
+
+`gcrane copy {{-h|--help}}`