This commit adds the `--verbosity` option to the `install tool` command.
MSBuild/NuGet output is now controllable by the user and defaults to being "quiet".
This enables users to see warnings from NuGet that otherwise would be swallowed
unless NuGet returned a non-zero exit code. As a byproduct of this change, the
exception handling and error messages related to obtaining tool packages was
retooled. We no longer display `install tool` command line help for installation
failures, as it should only be displayed for command line syntax errors.
Fixes#8465.
