[JS] Repackage Genkit NPM packages

[apascal07]

Describe the bug genkit-cli should become the CLI. genkit should become the meta package for all Genkit framework packages (currently genkit-ai). npx create-genkit should become an alias for genkit init.

[cabljac]

I've opened a PR to rename @genkit-ai scope to @genkit. Do we really want to rename genkit to genkit-cli?

To me at least, npm install -g genkit seems nicer than npm install -g genkit-cli

[cabljac]

nvm, i see why it is useful to switch to -cli

[pavelgj]

duplicate https://github.com/firebase/genkit/issues/390