Move partial goreleaser config to Go code

[mowies]

The partial configuration option for the goreleaser files was hardcoded in #478 as a hack/workaround. Since the goreleaser Go config was updated in goreleaser/goreleaser#4635 and released, we can now move this to Go code next to the other configuration options now.

Example of config section:

opentelemetry-collector-releases/distributions/otelcol-contrib/.goreleaser.yaml

Lines 1 to 2 in ee3ebeb

	partial:
	by: target