refactor: shift management

[Anurag810]

Shift Assignment:
Previously user needs to assign shift daily.
There should be an active shift for a period if there is an end date else it is an ongoing shift.

Shift Request:

New approval system and approver for Shift Request. on approval shift assignment is created automatically.

Employee:

New section Approvers With New Field Shift request Approver. Set Employee Wise Shift request Approver.

Department:

New child Table Shift request Approver to set Department wise shift Approver.

Docs
frappe/erpnext_documentation#123

[karthikeyan5]

Need to change this line to reflect the changes in Shift Assignment:

erpnext/erpnext/hr/doctype/shift_type/shift_type.py

Line 82 in 165d57a

filters = {'date':('>=', from_date), 'shift_type': self.name, 'docstatus': '1'}

[marination]

1. Add a title like Ongoing Shift, make employee bold and also shift type and name bold too
   

2. Add popup feedback (assignment created) on submitting approved shift request

[karthikeyan5]

Auto Attendance related changes LGTM.

[Anurag810]

Auto Attendance related changes LGTM.

yeah tested it with Marica

[Anurag810]

@marination frappe/erpnext_documentation#123

[marination]

Patch for Shift Assignment

[Anurag810]

@marination please check.