Allow to use custom templates

### Prerequisites

- [x] I have written a descriptive issue title
- [x] I have searched existing issues to ensure the feature has not already been requested

### 🚀 Feature Proposal

For the `generate` command, add a new `--template` CLI arg that would define what actual template to use, instead of just only the built-in ones. It can be a path to a local folder, so files would be copied from there instead of from the location of the built-in templates, or an url, so the content would be downloaded from there, for example from a git repository.

### Motivation

I would like to have a pre-defined template with some custom plugins, and this way would be easier than using a cookies-cutter or an install script.

### Example

_No response_