First step in the Conversation model update: Replace subject, message and metadata fields with name and config.
Remove obsolete metadata field and fix everything that was using it.
Add indexes and status field to Conversation model and update the world to use it.
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model

Conflicts:
	go/apps/multi_surveys/templates/multi_surveys/show.html
	go/apps/multi_surveys/templates/multi_surveys/surveys.html
	go/apps/surveys/templates/surveys/edit.html
	go/apps/surveys/templates/surveys/show.html
	go/conversation/templates/generic/includes/conversation-box.html
	go/conversation/templates/generic/show.html
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model

Conflicts:
	go/apps/sequential_send/tests/test_vumi_app.py
Update to use new migration method naming.
Clean up Conversation migrator and move it to its own module.
Clean up some bits and pieces left over from intermediate attempts at this stuff.
Tyop fix.
Deduplicate active and running conversation lists.
Management command to migrate conversations.
Tests for the conversation migration script.
Better help for go_migrate_conversations.
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model

Conflicts:
	go/conversation/base.py
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model
Better output handling in conversation migration tool.
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model
Merge branch 'develop' into feature/VUMIGO-238-new-conversation-model