Fallback to Global Binaries

[evanplaice]

Currently, ESMTK works great as a local dependency but when called remotely it attempts to load the binaries from the wrong location.

Instead, it should fallback to loading the globals if they exist and bail out with a sensible error if they don't.

Requirements:

• util to locate the global bin director
• util to determine if the bin file exists
• modifications to all existing commands

Notes:

• should work with npm_config_prefix
• should work with Windows
• should work with Homebrew
• should work with nvm/fnm

References:

• [is-installed-globally - GitHub](https://github.com/sindresorhus/is-installed-globally/blob/master/index.js
• global-dirs - GitHub