SyncMap is a matter of artifact type, not builder

[dgageot]

Fixes #3448

[codecov]

Codecov Report

Merging #3450 into master will increase coverage by 0.4%.
The diff coverage is 77.77%.

Impacted Files	Coverage Δ
pkg/skaffold/sync/types.go	100% <ø> (ø)	⬆️
pkg/skaffold/build/build.go	0% <ø> (ø)	⬆️
pkg/skaffold/build/local/local.go	60% <ø> (+5.45%)	⬆️
pkg/skaffold/build/gcb/types.go	31.25% <ø> (+3.47%)	⬆️
pkg/skaffold/build/cluster/types.go	100% <ø> (ø)	⬆️
pkg/skaffold/runner/diagnose.go	12.5% <0%> (ø)	⬆️
pkg/skaffold/sync/sync.go	77.61% <100%> (+1.42%)	⬆️
pkg/skaffold/docker/syncmap.go	67.16% <100%> (ø)	⬆️
pkg/skaffold/runner/dev.go	67.28% <100%> (+0.62%)	⬆️
pkg/skaffold/docker/image.go	77.27% <0%> (+0.9%)	⬆️
... and 4 more

[briandealwis]

I had been hoping to use this SyncMap() function for #2211 to help the IDEs to identify the application source roots in both the local workspace and remote images. Looking through this PR, I don't think this would have worked 😭. I wish there was a way to avoid these big switches though.

[nkubala]

@briandealwis ok with the new function name?

[briandealwis]

Oops, sorry — didn't mean to block it. LGTM.