v0.1.2: CCSR Diagnosis Categories

main features:
[DONE] - created ccsr diagnosis seed files
[DONE] - added encounter_type to encounters source table (needed by ccsr logic)
[DONE] - created models for ccsr diagnoses
[DONE] - created documentation for ccsr diagnosis models

other updates:
[DONE] - updated source abstractions to follow dbt best practices and prep for package release on dbt hub
[DONE] - updated documentation for chronic_conditions and staging sections of dbt project