refactor(ng-dev): introduce utility for reading buffer from stdin
refactor(ng-dev): introduce utility for reading buffer from stdin

Introduces an utility for reading buffer/text from process stdin. This
will be useful for delivering larger data from the release tool to
external commands. Command line arguments are not sufficient-enough
sine they suffer from escaping problems and max-length limits.

angular/dev-infra,angular/dev-infra,angular/dev-infra,angular/dev-infra