fix(developer): publish @keymanapp/keyman-version to npm

Fixes #7582.

Because of https://github.com/npm/cli/issues/3466, we must publish our
internal dependency @keymanapp/keyman-version. This change adds a common
builder function builder_publish_to_npm in build-utils-ci.inc.sh to help
with that task, which should be adopted by other scripts that need to
publish to npm, in the future.

For now, responsibility for publishing keyman-version is delegated to
kmlmc. In the future, we will move this to a single top-level build
action that publishes all npm modules across the entire repo for the
given version.