Allow overriding/skipping of OS detection

What would you like to be added:

The ability to optionally override or bypass the Environment (specifically linux.Release detection) used by catalogers during a scan.

Why is this needed:

1. Currently, Syft attempts to resolve linux.Release information for every scan. This presents a few challenges:
2. Directory Scans (Non-Root): When scanning a specific directory source that is not the root of an operating system (e.g., a subfolder containing application code), the automatic linux.Release detection might be irrelevant, potentially lead to incorrect assumptions, or add unnecessary processing time. In such scenarios, it would be beneficial to either:
- Skip the OS detection entirely.
- Allow the user to explicitly specify the target operating system if it's known, overriding the default detection.

File Catalogers: For catalogers that primarily focus on file content (e.g., language-specific package managers), the resolution of linux.Release often provides limited value and could be an unnecessary step. Providing an option to bypass this for relevant catalogers could streamline the scanning process.

Start by tracing how scans resolve the Environment, especially linux.Release, and how that value is used by catalogers. Compare directory scans with file-focused catalogers and identify the configuration or scan entry points involved. Done means the intended behavior for skipping detection and explicitly overriding the target OS is defined, including how it is tested.

Written by the indexing model from the issue text.