build: use enry to detect low priority files (#829)
This is a much more robust detection mechanism. Additionally we have
these signals we can also add in:
func IsConfiguration(path string) bool
func IsDocumentation(path string) bool
func IsDotFile(path string) bool
func IsImage(path string) bool
My main concern with this change is generated file detection on content
using up RAM or CPU. Will monitor this impact on pprof in production.
Test Plan: go test.