Add verbose mode to 'dojo version'

[rishson]

Under --verbose or similar, output the physical location of each installed command. We should also update the dojo help text to include a section on command loading precedence (and add to the enhanced version command)

e.g.

$ dojo version -verbose

build (dojo-cli-build-webpack) 2.0.0 (global)
anothercommand (dojo-cli-another-command) 2.0.0 (/path/to/pwd/node_modules)

You are currently running dojo-cli 2.0.0

Command loading
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Bit about where we look for commands and the resolution order...

[kitsonk]

Closing in favour of #134