Suggest Not Including data context discussion in "understanding-dataloader.md"

[chillicream]

Suggest Not Including data context discussion in "understanding-dataloader.md"

[gojanpaolo]

@michaelstaib I also think there are parts that discusses EF / db that we could remove and/or move to have more focus on graphql and HC.
What do you think of these action items?

• Write up a session 0 explaining the the data classes, db setup, some ef stuff, etc
• Automatically create database on Startup (this should also resolve #38)
• Ensure all sample code work (especially mutation) because it may fail a constraint with the full sql schema
• Remove db Migrations
• Remove "Configuring EF Migrations"
• Seed database with test data (see #15 (comment))
• Remove "Adding the remaining data models"
• Go straight to using IDbContextFactory and UseApplicationDbContext