- update link to query builder guide
- update link to model guide
- update link to behaviors guide
- update link to database basic guide

[ci skip]

fixes #2852

fixes #3302

Fixes #3179: removed duplicate validation rules from User model in advanced app, removed User::create()

fixes #3252

also improved unit tests for querybuilder buildLikeCondition

corrected app dir example and removed license code from example.