Also read `license-mapping-override.json` to allow overriding license mapping

Change the code for [resolveFuzzyMatching()](https://github.com/CycloneDX/cyclonedx-core-java/blob/8a4d83e05889373024c3ea7ef1f630b35394e7ae/src/main/java/org/cyclonedx/util/LicenseResolver.java#L160)

In addition to `license-mapping.json` also read `license-mapping-override.json` and use the values from this file with priority.

This will allow end users to define their own mapping.
You can easily override the classpath in [Maven](https://github.com/jakub-bochenski/example-cyclonedx-core-java/blob/master/pom.xml#L51-L61) or Gradle.

Right now I'm building my own fork of `cyclonedx-core-java`, but I'm only interested in changing this file.
Allowing users to just provide this file on the classpath would be much easier than having to rebuild the whole library.

ATM I could just copy the `license-mapping.json` and change it and provide on the classpath, but
- it easily gets out of sync with upstream
- classpath order can be problematic