Use dotnet-licenses for publishing

When we publish our compiler bundles and dotnet tool, we publish several dependencies alongside them. These packages have their own licensing policies, and we have to follow them — mainly, list the authors of the packages and their license texts.

Currently, I did a set of hacks and manual actions that provide these and include where appropriate, but eventually I hope that [dotnet-licenses](https://github.com/ForNeVeR/dotnet-licenses/) will allow to automate it.

Until then, we'll have to perform certain manual actions during release.

See several places in code marked with `TODO[#839]` and the corresponding actions in the `MAINTAINING.md`.