plugin: dir: implement import content type

in DirPlugin and not Plugin (because of cyclic dependency of
Plugin -> OVF -> Storage -> Plugin otherwise)

only ovf is currently supported (though ova will be shown in import
listing), expects the files to not be in a subdir, and adjacent to the
ovf file.

listed will be all ovf/qcow2/raw/vmdk files.
ovf because it can be imported, and the rest because they can be used
in the 'import-from' part of qemu-server.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>

src/test/path_to_volume_id_test.pm

@@ -190,6 +190,14 @@ my @tests = (
 	    'local:vztmpl/debian-10.0-standard_10.0-1_amd64.tar.xz',
 	],
     },
+    {
+	description => 'Import, ovf',
+	volname     => "$storage_dir/import/import.ovf",
+	expected    => [
+	    'import',
+	    'local:import/import.ovf',
+	],
+    },
 
     # no matches, path or files with failures
     {
@@ -237,6 +245,11 @@ my @tests = (
 	volname     => "$storage_dir/images/ssss/vm-1234-disk-0.qcow2",
 	expected    => [''],
     },
+    {
+	description => 'Import, non ova/ovf/disk image in import dir',
+	volname     => "$storage_dir/import/test.foo",
+	expected    => [''],
+    },
 );
 
 plan tests => scalar @tests + 1;