[Feature]: Add custom registry support

[Ben-Vollrath]

Describe the feature

Add support for custom registries like shadcn main (https://ui.shadcn.com/docs/registry)

Use case:
Custom registries that follow the shadcn philosophy can be added, providing more value for the vue ecosystem.

Additional information

• I intend to submit a PR for this feature.
• I have already implemented and/or tested this feature.

[unrevised6419]

It would be even cooler if the teams (React/Vue) agreed on some unified shadcn cli, that in the future could be used with any library/framework.

[Ben-Vollrath]

I have been working on this here.
My current version allows setting a custom registry base url, which would in turn use a completly different registry for everything.

Another solution I could think of would be allowing to pass a url to a single component in a different registry while still using the shadcn base registry for colors and base components.

TLDR:
Approach 1: support parallel registries to Shadcn-vue with custom registries

Approach 2: support building on top of Shadcn-vue with custom registries

I prefer Approach 2, but I would appreciate some feedback!

[ieedan]

It would be even cooler if the teams (React/Vue) agreed on some unified shadcn cli, that in the future could be used with any library/framework.

Over the last few months I have been working on jsrepo it allows you to use React, Vue, Svelte and more without having to manually configure a json file like you have to do at the moment with custom shadcn registries.