Add actual license text to JSON output

## Expected Behavior

Only the path to the license file is available in the JSON.

## Actual Behavior

Have the actual content of the license file available in the JSON.

## Steps to Reproduce the Problem

1. Run aspect to generate the licenses JSON output

## Specifications

- Version: latest
- Platform: Linux

Start by tracing the aspect invocation that generates the licenses JSON and the code that currently emits only the license-file path. Done means the JSON includes the license file's actual content as well as its path, verified by running the Linux reproduction steps.

Written by the indexing model from the issue text.