Add image_payload column to chats table.
Add Base64Image to chat struct.
Add ImageChange event to propagate image.
Change EditChat API - use CroppedImage.
Process and crop image in EditGroupChat.
This commit does a few things:
1) Handle membership updates using protobuf and adds the relevant
endpoints.
2) Store in memory a map of chats + contacts for faster lookups, which
are then flushed to disk on each update
3) Validate incoming messages
Sorry for the large pr, but you know, v1 :)