Installing azure-functions-core-tools through NPM

[priyaananthasankar]

With this PR we want to ask the question if there's a way to let the cloud shell user manage the installation and update of azure functions core tools. The ideal package system can be NPM https://www.npmjs.com/package/azure-functions-core-tools - since cloud shell has NPM available, this could be an approach to install this without a global installation which might require root access.

If this is possible, proposing to remove the azure functions core tools from base image installations and future Mariner installations.
cc: @darrentu
azure functions core tools is about 670MB in the image.

Eventually we apply this pattern for future package request. What kind of installers does your package support other than OS mirrors? and is it possible for a user to install it without root access?