[Enhancement] reduce cost of ember new, buy copying the CLI’s own struct...

...ure

in theory symlinking would be instance, but since in npm each project gets it’s down unique tree of dependencies

before: 34.93s user 12.20s system 126% cpu 37.313 total
after: 13.29s user 6.59s system 119% cpu 16.578 total


this breaks some of our tests (which do something similar), merely posting this as an idea.. @rjackson thoughts?