VS Code and VS extensions don't provide actionable error messages

[bamarsha]

There are several bug reports featuring error messages from the Visual Studio Code and Visual Studio extensions:

• Visual Studio Code: Could not download Q# language server. Could not download Q# language server. #498
• Visual Studio: "error activating the remote language server. Q# Language Extension" "error activating the remote language server. Q# Language Extension" #388
• Visual Studio Code: Project creation failed. The Q# project template may not be installed. Project creation failed. The Q# project template may not be installed. #354

These error messages don't provide enough information for the user to solve the problem, and they don't provide enough information for us to find the cause. While more detailed logs exist (Help -> Toggle Developer Tools in VS Code and Activity Log in VS), it's not easy to find these logs unless you already know where to look.

I think the extension error messages should:

• Include more informative error details directly in the message.
• Include a button to open more detailed error logs, or instructions for where to find them.