catapult: move //catapult/cmd to //cmd

testutil will have the same structure within testing. It's best to keep
things uniform

IN-199

Change-Id: Ib5b2acc6ab68c15d72117d0dd45a50fffd7c5249
diff --git a/catapult/cmd/catapult/main.go b/cmd/catapult/main.go
similarity index 100%
rename from catapult/cmd/catapult/main.go
rename to cmd/catapult/main.go
diff --git a/catapult/cmd/catapult/make_histogram.go b/cmd/catapult/make_histogram.go
similarity index 100%
rename from catapult/cmd/catapult/make_histogram.go
rename to cmd/catapult/make_histogram.go
diff --git a/catapult/cmd/catapult/upload.go b/cmd/catapult/upload.go
similarity index 100%
rename from catapult/cmd/catapult/upload.go
rename to cmd/catapult/upload.go