Multi-parent space avatar support for space and chats

[emilvincentz]

Now that a user can link/unlink spaces and chats, we also need to update the avatars. E.g.

• Unlinking a chat from one space and linking to another space, should also update the avatar to the corresponding space logo.
• Linking a chat/space to multiple spaces, should also reflect in the UI (see designs from design team)