Add optional parameter to generate_base_models with a select *

[davesgonechina]

resolves #

This is a:

• [ ] documentation update
• [ ] bug fix with no breaking changes
• [x] new functionality
• [ ] a breaking change

All pull requests from community contributors should target the main branch (default).

Description & motivation

Adds select_star parameter to generate_base_model to allow users to choose whether the base model explicitly includes column from the source or always includes all columns available from the source table. This can reduce base maintenance chore overhead especially when coupled with the materialization='view' parameter.

Checklist

• [ ] This code is associated with an issue which has been triaged and accepted for development.
• [ ] I have verified that these changes work locally
• [ ] I have updated the README.md (if applicable)
• [ ] I have added tests & descriptions to my models (and macros if applicable)
• [ ] I have added an entry to CHANGELOG.md