…fault

Previously this package was installed in the default `dependencies` section
of `package.json`, but this meant that its own dependencies are treated as
dependencies of the main project: Babel, for example.

Generally, $localize` is not used at runtime - it is compiled out by the
translation tooling, so there is no need for it to be a full dependency.
In fact, even if it is used at runtime, the package itself is only used
at dev-time since the runtime bits will be bundled into a distributable.
So putting this package in `devDependencies` would only prevent libraries
from bringing the package into application projects that used them. This
is probably good in itself, since it should be up to the downstream project
to decide if it wants to include `@angular/localize` at runtime.

This commit changes the default location of the package to be the
`devDependencies` section, but gives an option `useAtRuntime` to choose
otherwise.

Fixes angular#38329

…` by default

…` by default