move spec to apm-data and stop syncing files

[kruskall]

See

apm-server/Makefile

Lines 223 to 224 in 98bcab0

	# TODO in the future we should probably trigger the updates from apm-data,
	# and just keep the JSON Schema there.

we should move the spec files to apm-data and stop running the sync on each PR, it's just wasting CI minutes

apm agents should be updated to use the apm-data spec