Allow for comments to be added to messages

[lanedirt]

For certain message types it should be possible to add comments. These comments should also show up when this message is shared with other players later.

Example where comments are possible in the official game: "Espionage Reports".

Example HTML of the comment form can be seen in:

• resources/views/ingame/messages/templates/espionage_report_full.blade.php at the end of the file.

Example screenshot in the official game: