Emails: Allow collapsing/expanding

When getting emails in the inbox, we currently have two distinct problems:

• When it’s a forwarded email, the content is empty and only opening the single view for that email shows the actual content, so it would be great o have an inline “expand” option

• On the other hand, long emails can’t be collapsed, which clutters the message history. Ideally, we’d have a way to have them collpased to the first 3 lines by default (or something along those line)