testing: add dev/fakehub command
Created by: ijt
Closes #3679 (closed)
This change introduces a new command called dev/fakehub that serves multiple copies of a local git repository over HTTP, along with a pastable config for easier manual testing of sourcegraph.
Test plan: Run the command locally like this: go run main.go -n 20 path/to/some/dir/with/a/.git/subdir
, then past the contents of localhost:9847/config into a sourcegraph instance and see if the results make sense.