Walkthrough Example: Development Practices

[sungchun12]

everything in #4108 plus:

• when to use skip backfill and empty backfill during development and how it works
• how to best use concurrent batches with easy math cheatsheet
• managing data for external clients with blueprint models using advanced macro techniques

This is a cobbling of many common advanced questions we get from the community and in sales calls. This will help give people a better mental model of how to approach fine tuning their development experience with sqlmesh.