Add ability to specify dependencies without foreign keys#32

Draft

mlb6 wants to merge 3 commits intodigilist:masterfrom

mlb6:feat/logical-dependencies

Commits on Dec 22, 2020

feat: add and/or operator to add logical dependencies
MLB
committed
test: add tests to cover new 'dependencies' configuration and fix for isNull/isNotNull
MLB
committed

Commits on Dec 23, 2020

feat: add dynamic dependencies with 'column_as_referenced_table'
MLB
committed