[IMP] mass_mailing: add creation date in fields
to display it on list view + perform search on it.
[IMP]project:change message start_date lower then end_date aadn change type of fields(new_task_description) and change icon of gantt chart in task form view in tab (extra_info)
[IMP]sale_sevice: remove date_deadline in method(_create_service_task) and change description of module feature
[IMP] [project_issue] : add string unit_amount fields in xml, move id fields for project_issue in xml, add help for task_id fields in py,change condition _can_escalate method in py.
[IMP] [project]: set default stage 'undefined' in project_task
[IMP] sale_service : remove assert of task date_deadline  == procurement date_planned
[IMP] sale_service: change description
[IMP] [project]: improve onchange_project methods.
[IMP] [projetc]:improve retrun for stage_find method.
[IMP] prjecet: change the constraint string and, sale_service: change description
[IMP]project : chnage in condition of (not section_id) and resolve indentation
[IMP] change help and move id group status to new group
[IMP] [project_issue] : remove group string in issue form view extra_info tab,[project_issue_sheet] : remove group
[IMP] sale_service :rename (Create Tasks on SO) into (Create Task form SO)