Merge branch 'fix_1529' into '7.4.0'

Fix for #1529 - Pre-Computation of username for better customization and performance.

**Impact Areas**

* Schedule Reports (receipients email)
* Group users fetched in listview
* User module Create / Update
* SMSNotifier
* Report sharing
* User privileges file computation
* Title shown on user icon in top bar
* Username in email print view
* USername in ics file sent for calendar invite
* User calendar (shared users list)
* Account tab in Campaigns module
* User signatur added in the email
* Helpdesk module - Getting list of open tickets
* Dashboard - Potential related default widgets and custom widgets
* Reports list view
* All module assigned_to field
* Users CRUD
* Owner field in all the views
* Fromname in workflow email task
* Username shown in Scheduled import result email
* Username sent in MailManager email
* Mobile - Fetching accessible user list for module.

See merge request !757