Remove Ideas and Topics.

[andorp]

Fix: #945 Fix: #998

[andorp]

The SchoolClass can be found in the following data definitions:

• Role
• IdeaSpace

The IdeaSpace can be found in the following data definitions:

• Topic
• DScope
• IdeaLocation

To remove an idea space, the implicit references from that idea space have to be cleared from the types listed above. My suggestion is

• to create a default location and set all the referenced entities (like: user, topic, etc) to that location,
• admin could add/change the user's role,
• students has to set their ideaspace related delegations again after new idea spaces are created

[andorp]

Correction based on the issue linked: Only ideas and topics have to be removed. Which makes life easier.

[fisx]

IdeaSpaces should not be affected by this change. we only want to delete ideas and topics. so @andorp your above comment is off-topic (but still interesting).