Review Hosting API

The CC external API also called JSRT could do with a review prior to the next release.

Roughly speaking it contains:
1. "Windows only APIs":
These are historic chakra.dll APIs that pre-date the cross platform nature of chakracore; they can actually be used on linux or macOS with some caution - notably they use strings that are rows of 16bit characters - normal on windows but not normal on other platforms.

1. Settled Chakracore APIs:
Methods included in version 1.11 and in most cases several previous versions - many of these are marked as "experimental" in documentation but in practise have been stable for some years and should probably be labelled as such.

1. Master only APIs:
Various APIs have been added in master, some of these are documented, some aren't - in particular several were added in #5923 that seem to follow a very different design philosophy to all the previous APIs. We should review these and consider removal or documentation on a case by case basis prior to a stable release.

Overall I think we should aim at maintaining an API with a clear design philosophy that works in a consistent way AND supports stability and is relatively easy to maintain - part of this is keeping it lean hence my aversion to some of the additions from #5923.