feat: Add options to configure pruning unused vertex attributes

[hichemfantar]

The code changes introduce two new options to the CLI tool:

• --pruneKeepAttributes: Determines whether to keep unused vertex attributes, such as UVs without an assigned texture.
• --pruneKeepLeaves: Determines whether to keep empty leaf nodes.

These options provide more control over the pruning process, allowing users to optimize the resulting glTF files based on their specific requirements.

closes #278 closes #280