[IMP] hr: job position: better state help + job positions are now open by default.
[IMP] purchase: added onboarding tip
[REM] project : Remove reviewer field
[IMP] crm: demo data update
[IMP] hr_timesheet, project: various usability-related improvements

hr_timesheet: merged use_timesheets and invoice_on_timesheets fields on account.analytic.account
that basically tells the same thing (project using timesheets). Propagated this change in
the various views using it.
project: various improvements in views to ease the user experience.
[ADD]crm: Added feature of 'Schedule/Log Call' for opportunity form view and couning no. of calls