[IMP] project, industry_fsm: Improve subtasks and configuration UX

Purpose
=======

In Project, the configuration has to be done twice: in the settings of the
app and on each project.

During the onboarding, the user won't understand that a feature has to be
enabled at both places and will think that the system just doesn't work.

If the user enabled a feature, he most likely intends on using it for most
of his projects. Therefore, having to do a double configuration for each
new project is annoying.

By the way, sub-tasks is the only global feature (it can't be enabled or
disabled by project), so we are breaking it down by project to remain
consistent with the rest.

Specification
=============

1/ Enable subtasks per project
Before this commit, sub-tasks were a global feature (i.e. once enabled
they were enabled for all projects). This commit gives the ability to
enable/disable sub-tasks per project.

2/ Make project_id on planning required

3/ Change default rating status on new projects

4/ Default value for allow_subtasks

5/ Enable timesheets on existing projects

6/ Hide Total Hours if subtasks are disabled

7/ Create project in the company context.
Otherwise some records generation could use a default company which is not
the company for which we want to create a project.

8/ Default value for allow_forecast, is_fsm

9/ Change reference to timesheet product

10/ Fix tracback on industry_fsm_report.
Before this commit, there was a traceback when enabling "Worksheets"
(industry_fsm_report) after "Time and Material" (industry_fsm_sale).

11/ Convert some onchange method into computed editable stored fields

closes odoo/odoo#41218

Taskid: 2146474
Related: odoo/enterprise#6998
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>
Co-authored-by: Yannick Tivisse <yti@odoo.com>