conversationFilter property

A filter to reduce conversation results to a specific subset.

The AuthorizedView's assigned permission (read/write) could be applied to the subset of conversations. If conversation_filter is empty, there is no restriction on the conversations that the AuthorizedView can access. Having authorizedViews.get access to the AuthorizedView means having the same read/write access to the Conversations (as well as metadata/annotations linked to the conversation) that this AuthorizedView has.