Remove dependence on old version of the qrcode-generator library and streamline the development artifacts and external API

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This set of changes aims to bring this project up to date with latest upstream developments, along with proper versioning of the declared dependencies and a switch to yarn tooling.

The dependence on an outdated version of kazuhikoarase/qrcode-generator has become an impedance to further development of this utility and equivalent or better ASCII rendering functionality is now part of the upstream library, and so this PR removes its implementation from the source code of this project and sets up a dependence on the latest upstream version of qrcode-generator.

Also, this PR fixes the unit tests and makes some small but material changes to the external API.

In terms of further development, it looks valuable to incorporate the ability to set the data mode, code type, and error correction level both when calling the node API and also when invoking this utility from the command line.

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@gtanner, would you please consider merging this?

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@mwbrooks, would you please take a look at this pull request?

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@gtanner, I hate to bug you but...