add ignore entry to chat view context menu
When a message is right clicked in the chat view, 'ignore' entry is missing.
To ignore a user I have to //type// '/query NICK' and right-click there, or right-click their nick in the user list. That's laborious and inconvenient; having the 'ignore' entry in the chat view context menu would be nice.
Note: quassel has a context menu for the chat view, not separately for each message, at present. That's have to be added.