Add subpackage for image registration

## Feature Request

### Description

Add an optional subpackage for registrating images before calculating metrics.

### Use cases

### Possible implementation

Add with import checking to make dependencies optional. [lcreg](https://github.com/p-roesch/lcreg) can be used.

### Alternative solutions

Look at the existing package structure in vIQA to understand how subpackages and optional dependencies are handled. The lcreg library must be integrated with import checking. Determine where image registration fits into the metrics calculation pipeline. A newcomer would need to design the subpackage's API and integration points.

Scritto dal modello di indicizzazione a partire dal testo della issue.