Support the template registration which has a compressed format .tar.gz and tar.xz

### The required feature described as a wish

As a User/Admin/Operator I would like to register whose template format is

resolute-server-cloudimg-amd64.tar.gz
resolute-server-cloudimg-amd64-root.tar.xz

Currently Cloudstack supports the registration of template whose format is

resolute-server-cloudimg-amd64.img
resolute-server-cloudimg-amd64.qcow2
resolute-server-cloudimg-amd64.qcow2.bz2
resolute-server-cloudimg-amd64.xz

it will be useful for the admin user who just wants to quicky register a small-sized compressed cloud image

Ref
https://cloud-images.ubuntu.com/resolute/current/

Start by tracing CloudStack's template registration path and how it recognizes the currently supported image formats listed in the issue. Confirm where format validation and archive handling occur; done means templates ending in .tar.gz and .tar.xz can be registered alongside the existing formats, with coverage for both cases.

Written by the indexing model from the issue text.