Fix for #1535 - Provide hooks to plugin custom connectors and avoid modification in core files

**Impact Areas**

* User sessions
* Inline cache

See merge request !761

Fixes #845 Updating packages during migration is generalized, instead of individual script level

See merge request !750

Adds "every 4 months" frequency to RecurringInvoice.service to be able to genera…

…te invoices every 4 months in SalesOrder module

See merge request !759

Es mx translation improvements

See merge request !758

Fixes #1534 Clean installation of vtiger 7.4.0 breaks

See merge request !762

Adds "every 4 months" frequency to RecurringInvoice.service to be able to generate invoices every 4 months in SalesOrder module

Fix for #1407 - 7.3 beta: Filter UI is broken

See merge request !746

Fix for #1437 - 7.3 beta: No text wrapping in related list

To apply ellipses you need to have constraint on width of the container. Because this was missing, content was taking width upto 80% of the table cell.

See merge request !747

Fix for #1454 - In Edit View currency type fields do not line up.

See merge request !748

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

Fix for #1520 - Eliminate MySQL CAST on datetime columns when expected value type is datetime.

**Areas validated**

Querygenerators
CustomView
Reports (all types) with grouping.
Calendar

See merge request !751

Fix for #1529 - Pre-Computation of username for better customization and performance. (Migration changes)

Fix for #1523 - Optimization of record label computation.

**Areas validated**

* User CRUD (both admin and non-admin)
* Create or Update records from workflows
* CRUD from APIs

See merge request !756

Fix for #1526 - Extend versioning support to all client side resources.

**Impact areas**
All JS and CSS assets loaded in all pages of CRM

See merge request !755

Patch to allow admins to edit/delete any Custom Views. Refs #706

See merge request !727

Fixes #1525 Quotes failing to email attached pdf documents

See merge request !754

Fix for #1523 - Optimization of record label computation (Generalizing data population for entity names)

Fixes #1511 Portal Download files results on zero length file

See merge request !749

Fixes #1510 Cleanup scheduled workflow count

See merge request !745