lb4 repository tool error if datasource is using injection

I have a simple data source, whos config is loaded via injection:

```
export class MainDataSource extends juggler.DataSource
implements LifeCycleObserver {
static dataSourceName = 'Main';

constructor(
@config()
dsConfig: object,
) {
super(dsConfig);
}
}
```

Application.ts:
`this.configure('datasources.Main').to(options.datasources?.Main || {});`

When running the repository scaffolding tool the following error occurs:
`(node:24064) UnhandledPromiseRejectionWarning: Error: Cannot load C:\lb4\src\datasources\main.datasource.config.json: ENOENT: no such file or directory, open 'C:\lb4\src\datasources\main.datasource.config.json'
`

I am temporarily suppressing the error by adding a `main.datasource.config.json` file in the source directory.

However, this scaffolding tool should not require a fully configured data source to generate simple repositories. If the configuration cannot be found, it should just emit a warning, but still allow the tool to run and generate a non-customized class using the basic boilerplate.

Start with the injected datasource setup in Application.ts and reproduce the repository scaffolding command using the missing src/datasources/main.datasource.config.json path. Trace how the tool handles the missing configuration, then verify that it warns and still generates the basic repository class without requiring the file.

Written by the indexing model from the issue text.