Add a `--noprepare` flag to `cordova run`

`cordova run` has the excellent `--nobuild` flag, which makes it possible to skip building (when `cordova build` is called manually).

Similarly, it would be neat if a `--noprepare` flag was available.

This allows for more fine-grained control over `run`.

In our case, we want to do adjustments to files after calling `cordova prepare` (similar to the hooks, but we've implemented it a bit differently), and this is impossible since `cordova run` will call `prepare`, undoing our changes.