Add permissioning for Delete action

Site admins need an option to prevent certain users from deleting records of various types.

For this implementation, we'll support this functionality using Drupal permissioning.

The following granularity will be offered for delete permissions:

• delete contacts
• delete activities

...plus

For each enabled component:

• delete in $component (e.g. delete in CiviContribute)

The component delete permission will apply to all objects in that components class tree.

For example, "delete in CiviEvent" allows delete of:

• participant records
• event records

Delete button, action link and batch actions should be suppressed for any user who doesn't have delete permission for that object (contacts) or for objects that belong to that component.