explore scancode.io as a replacement for including scancode-toolkit as a library

### Description

Currently, [nexB/scancode-toolkit](https://github.com/nexB/scancode-toolkit) is compiled into the [clearlydefined/crawler](https://github.com/clearlydefined/crawler) Docker image and used as a library. As a result, a new image of the crawler has to be built whenever we want to upgrade to a later version of scancode-toolkit. Long term maintenance of the ClearlyDefined ecosystem would be easier if scancode is a separate service that runs from its own Docker image.

We are unable to use scancode-toolkit as a Docker image because it only provides command line access and does not have an API. It is possible that another tool, scancode.io, produced by nexB has an API that can be used as a Docker service to run scancode-toolkit.

Toward that end, explore [nexB/scancode.io](https://github.com/nexB/scancode.io) to determine if it has an API to run the scancode process and produces a Docker image that allows scancode to run as a separate service. If there isn't a Docker image, we can help create one and publish it to ghcr.io.

### Related Work

* https://github.com/clearlydefined/crawler/issues/502