Build conda packages for IQ#, qsharp.py

[cgranade]

This PR prepares for distributing IQ# and the qsharp Python as conda packages, making it easier to install native dependencies at the same time.

[cgranade]

@anpaz-msft @bromeg: Based on offline discussion, it sounds like we have an action plan for moving forward. Namely, we'll drop the dotnetcore-sdk and pwsh packages, making sure to document that any contributors (not users!) who want to build the iqsharp and qsharp packages locally need both of those requirements installed out-of-band. This will mean that:

• A Python user who wants to use IQ# will only need the qsharp conda package to run Q# from a Python host, and all other requirements will be brought in as dependencies automatically.
• A Python user who wants to develop Q# code from within Visual Studio Code will need to install the .NET Core SDK out-of-band to use intelliSense features, and will automatically be prompted to do so by the Visual Studio Code extension.