2. Update Column Name from milestone_id to milestoneId

# Conflicts:
#	src/main/java/com/ffii/tsms/modules/data/service/PositionService.kt
#	src/main/java/com/ffii/tsms/modules/data/service/SalaryService.kt
#	src/main/java/com/ffii/tsms/modules/data/web/SalaryController.kt

- save
- get the list (name, code, description)
2. Add Position API
- save
- get the list (name, code, description)

Reviewed-on: https://git.2fi-solutions.com/davidhui/TSMS-backend/pulls/2