Support a similarity search by full license text

[sschuberth]

Given an arbitrary full license (plain) text, it would be cool if we could do a similarity search and get those entries listed whose texts are similar. The metric of "similar" would need to be defined, plus maybe some sort of threshold would need to be configurable; but maybe that's already going too far, and just some simple similarity search with sane defaults would suffice.

[pombredanne]

@sschuberth That's an excellent idea! we may have an aspiring contributor with @adii21-Ux for a closely related GSoC project idea: https://github.com/nexB/aboutcode/wiki/GSOC-2022#scancodeio--scancode-toolkit-create-web-application-to-scan-and-review-a-single-license-text

The idea is to run ScanCode license detection on some input text which is the essential similarity search for this!
I think we could extend this to add a threshold and present not one single match but all the matches found with scores... and show a visual diff of sorts... this could be extended to other text similarity metrics too.