container config: add CreateCommand

Store the full command plus arguments of the process the container has
been created with.  Expose this data as a `Config.CreateCommand` field
in the container-inspect data as well.

This information can be useful for debugging, as we can find out which
command has created the container, and, if being created via the Podman
CLI, we know exactly with which flags the container has been created
with.

The immediate motivation for this change is to use this information for
`podman-generate-systemd` to generate systemd-service files that allow
for creating new containers (in contrast to only starting existing
ones).

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

test/e2e/inspect_test.go

@@ -117,6 +117,18 @@ var _ = Describe("Podman inspect", func() {
 		Expect(len(result.OutputToStringArray())).To(Equal(1))
 	})
 
+	It("podman inspect container and filter for CreateCommand", func() {
+		SkipIfRemote()
+		ls, ec, _ := podmanTest.RunLsContainer("")
+		Expect(ec).To(Equal(0))
+		cid := ls.OutputToString()
+
+		result := podmanTest.Podman([]string{"inspect", "--format={{.Config.CreateCommand}}", cid})
+		result.WaitWithDefaultTimeout()
+		Expect(result.ExitCode()).To(Equal(0))
+		Expect(len(result.OutputToStringArray())).To(Equal(1))
+	})
+
 	It("podman inspect -l with additional input should fail", func() {
 		SkipIfRemote()
 		result := podmanTest.Podman([]string{"inspect", "-l", "1234foobar"})