#153 Implement consistent delete policy

[Miro Halas]

This needs to be documentted in dictionary for EVERY
data entity when is it going to be deleted and what
other data entities it influence and in what manner

This table shows in the header data entity and where in
the GUI is it deleted and the effect on othe entities.

IndexPages - INBOX - INDEX
--------------------------
nothing to do
When indexed, delete

TrackingDocuments - FILES - FILE - File Edit
--------------------------------------------
Index pages - reset reference
Tracking baches - delete all which do not have assigned
any Tracking document
Tracking page - delete

DocumentPages - INBOX - INDEX - IndexPage Index
(Replace document page)
- INBOX - INDEX - Document Index (Remove pages)
- FILES - DOCUMENT - Document Edit (Remove pages)
----------------------------------------------------------------
Index pages - reset reference
Tracking pages - reset reference to document pages
Tracking documents - reset reference to document if no
recieved Tracking page, reset reference to file for ALL
tracking documents under this Tracking batch if no
recieved Tracking page under this Tracking batch and
file not specified

Documents - FILES - DOCUMENT
- FILES - FILE - File Edit
------------------------------------
Index pages - reset reference
Tracking pages - delete
Tracking documents - delete
Tracking Batch - reset reference to file for ALL
tracking documents under this batch if no recieved
Tracking page under this Tracking batch and file not
specified
Document pages - delete
Document Attribute value - delete

Files - FILES - FILES
---------------------
Index pages - reset reference
Tracking pages - delete
Tracking documents - delete
Tracking batch - delete
Documents - delete
Document pages - delete
Document Attribute value - delete
File Attribute value - delete

File types - TEMPLATES - FILE TYPES
-----------------------------------
Not to allow to delete File types if File referenced to
file type exists

Document templates - TEMPLATES - DOCUMENT TEMPLATES
---------------------------------------------------
Do not allow to delete Document template if document or
tracking document exists
Index pages - reset reference

Categories - TEMPLATES - CATEGORIES
-----------------------------------
Do not to allow to delete Categories if Document
Template under this category exists

Entities - TEMPLATES - ENTITIES
-------------------------------
Do not allow to delete Entities if File Type under this
category exists
Index pages - reset reference

Attributes - TEMPLATES - FIELDS
-------------------------------
Do not allow to delete Attributes if refrenced value
exists or if it is used in file type of document template

User - SECURITY - USERS
-----------------------
For now, do not allow to delete user if some status
change for this user exists. We will need to come back
to this.
Received file - reset reference to user
Index pages - reset reference to Last Indexer
Tracking batch - reset reference to Creator
Tracking document - reset reference to Creator
Documents - reset reference to Manager, Maintainer,....
Document pages - reset reference to Indexer
Files - reset reefrence to Manager, Maintainer,....
Status changes (File, Document) - see above