[Feature Request]: Writing Parameters via ETL Metadata

### What would you like to happen?

It would be beneficial to have an option in the ETL metadata to pass variables and parameters to the pipeline model.

Regarding parameters, ideally, the default value of each parameter in the pipeline should be defined. This would facilitate debugging. Often, values ​​for steps like lookup and insert are variable fields passed from a pipeline to a subpipeline via parameter and then passed to the pipeline model via ETL metadata. However, when testing the pipeline model generated by the ETL metadata, it is necessary to specify this variable repeatedly, which slows down the process. If possible, setting the parameter value and defining variables directly would simplify the process.

### Issue Priority

Priority: 3

### Issue Component

Component: Transforms

Start by reviewing how ETL metadata creates the pipeline model and how pipeline and subpipeline parameters are currently passed. Define the expected behavior for metadata-supplied variables, parameters, and parameter defaults, including how those values are used when testing the generated model.

Written by the indexing model from the issue text.