Improve documentation

Address content gaps in documentation for Model Builder and ML.NET CLI

## Docs tracking issue

dotnet/docs#32112

## Work Items

## Related Issues

- [ ] Train an ML.NET model in Azure using ML.NET CLI. Source: https://devblogs.microsoft.com/dotnet/training-a-ml-dotnet-model-with-azure-ml/
- [ ] Train an ML.NET model in Azure using the [Azure ML SDK](https://www.nuget.org/packages/Azure.ResourceManager.MachineLearning/1.0.0-beta.2)
- [ ] Document best-practices
- [ ] Sharing and reusing code.
- [ ] Create a SQL view from custom SQL query and import into Model Builder
- [ ] How to create an ML.NET custom environment using [Dockerfiles](https://github.com/dotnet/machinelearning-modelbuilder/tree/main/Dockerfiles)
- [ ] Use [Code Example label](https://github.com/dotnet/machinelearning-modelbuilder/issues?q=is%3Aopen+is%3Aissue+label%3A%22Code+Example%3F%22) to identify potential content gaps @luisquintanilla
- [ ] Create sample using DataWrangler and ML.NET

Individual work items to be tracked in [dotnet/docs](https://github.com/dotnet/docs/issues?q=is%3Aopen+is%3Aissue+label%3Adotnet-ml%2Fprod) repo

## Dependencies

- Features need to be available in Model Builder / ML.NET CLI in order to document