* [ADF-1958] Process Attachment list - The empty list should be a simple template
* changed the default empty list to a simple template
* changed process-attachment.component.html so that the user can pass custom empty tempate
* [ADF-1958] Process Attachment list - The empty list should be a simple template
* changed the default empty list to a simple template
* changed process-attachment.component.html so that the user can pass custom empty tempate
* removed some unused variables
* [ADF-1958] Process Attachment list - The empty list should be a simple template
* changed the default empty list to a simple template
* changed process-attachment.component.html so that the user can pass custom empty tempate
* [ADF-1950] Not able to open an attached file within a Task.
* Changed data-column key 'icon' to 'image' in task/process attachment file component.
* Refactored activiti-component.
* Used Adf-viewer to view the attached documents.
* [ADF-1950] Not able to open an attached file within a Task.
* Centralized the use of the adf-viewer component in the activiti component (demo shell folder).