Ever since Meteor 1.3 first introduced a module system based on something
other than `Npm.require`, we've continued throwing missing module
exceptions that refer to `Npm.depends` and/or `Npm.require`, even if the
developer called `require` or used an `import` declaration. This commit
fixes that, so that all missing module exceptions look like 'Cannot find
module "module/name"'.
I also noticed recently that `Npm.require` is capable of returning modules
installed in `node_modules` directories completely outside the app, which
is bad news for development/production reproducibility. Fixed that too.
CC @hwillson who has spoken of deprecating `Npm.require` entirely, and
just using `require` everywhere, instead.
Now anyone can define meteorInstall.fetch however they see fit, and the
install.js implementation will handle everything else.
This separation of concerns leads to significantly less code, too.