update rails 414
rename etudes en cours to etudes
various changes to etudes:
- 'etudes en cours' -> 'etudes'
- added created_at column in list
- fixed etudes link in public navbar
- using state enum for workflow state
- adding access enum field for public/private items
- table: show ongoing/finished records differently
- added fichier field to etude, fix views
allow deleting current fichier for documents