Create jsii-transpile tool

[eladb]

Goal: given a jsii-enabled package (e.g: the npm tgz for the package), install the package & dependencies into a working directory, compile & transliterate all code examples therein into select target languages, then produce a transliterated .jsii assembly file as a result.
How: jsii-rosetta provides the functionality to perform the transliteration, however it does not bother with the dependency management (it is intended to run at build time, not against packaged libraries), and produces a rosetta tablet file instead of a transliterated jsii assembly document.

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The jsii-transpile tool would consume a .jsii assembly file, and leverage jsii-rosetta APIs to create one <lang>.jsii file per configured target language, with all APIs renamed to the correct language representation, and sample code trans-literated to the correct language where possible.

[eladb]

NOTE: It's important that it will be possible to run this tool in parallel (i.e. each language in a separate job)

[RomainMuller]

Implemented a jsii-rosetta transliterate tool instead. This doesn't do exactly the same job (it only does the transliteration, and the dependency resolution, etc... is left to the user, who's more likely to know exactly how to make this happen).