Bug resolved for collection display in groups

Previously , collections for groups were not displayed due to overriding the "related_content" block in groupdashboard template. 
Now its displayed according to group status ("DRAFT" or "PUBLISHED")

Modification in : 
```
base.html  -->  Included block "collection_content" (Block which is restricted to collection display only)
page.py  --> During publish made the distinction according to their "_type"
group.py  --> code added for breadcrumbs_list and collections display according to group status.
node_details_base.html  -->  block "collection_content" added
```