Refactor template.config into separate config files per template

### Issue Description:

Currently, all templates are configured within a single `template.config` file, which has grown complex and difficult to maintain due to the number of flags and switches used to differentiate templates. This has created a "Big Ball of Mud" scenario, slowing down development and complicating the addition of new templates.

The goal of this refactoring is to split the existing `template.config` into individual configuration files, one per template. This will:

- Simplify development by isolating template-specific configurations, reducing the likelihood of errors affecting all templates.
- Improve maintainability by making it easier to add new templates—simply create a new config file for each template and describe which files are included.
- Enable the template engine to automatically read the namespace of the current project when the config file is placed in the same folder as the project file (`.csproj`), reducing the need for the user to re-enter the solution and module names.
- Show help specific to the selected template when running the `--help` flag, instead of displaying parameters for all templates.

Instead of running:

```ps1
dotnet new modulith `
--add basic-module `
--module-name Shipments `
--solution eShop
```
The new syntax will simplify the process to:
``` ps1
dotnet new modulith --type basic --module-name Shipments
```
Additionally running the `--help` flag will show help for the specific template selected instead of showing the parameters for all templates