[TASK] Support multiple templates in the CLI

[Serial-ATA]

Overview

cargo tangle gadget create currently just pulls from the hello world template: https://github.com/tangle-network/blueprint-template

It'd be nice to add:

• --repo and --path to specify remote & local templates to use instead
  • I already have this done locally, will get it in once this is no longer a side task.
• In the absence of flags, show the user a list of templates to choose from:

$ cargo tangle gadget create

Choose a template
> 1. Base (A simple hello world template) [default]
2. [name] (description)
3. [name] (description)
...

This would be sourced from a list maintained in create.rs (with entries only coming from the tangle-network org, preferably).

Currently not useful at all, we don't have any extra templates.