Make possible to set a custom template for a new project

[ofabianomartins]

This pull request enable loco new command use a custom start template by setting a new option --template-dir the direct to especif folder

[kaplanelad]

Thanks for the contribution! A few things:

1. Naming: --template-dir doesn't clearly convey what happens, the user is providing a custom starter project to scaffold from. Something like --from or --starter-path might be clearer: loco new --from ./my-custom-starter.
2. Tests: Please add tests, at minimum, test with a valid template directory and with a missing/invalid one.
3. Validation: Validate that the directory exists and contains the required structure (e.g., setup.rhai) before processing, with a clear error message if something is missing.

[ofabianomartins]

Thanks for feedback, i will work on it.

[ofabianomartins]

@kaplanelad i made update you asked. Could review please.

[kaplanelad]

Hey @ofabianomartins, thanks for the effort on this! Unfortunately I'm going to pass on merging this PR. The feature introduces git cloning, zip downloading, and HTTP fetching into loco new, which significantly increases the attack surface of a CLI tool that runs with full user privileges.