Include chat in Machine Translation Budget

[svenseeberg]

The used translation budget should also show the fraction of the budget that has been spent on the chat. The used budget already includes the chat. But we can show the fraction that has been spent on the chat in a different color.

There is one catch: We only have a start and end date of chats and the total amount of spent words. We deduce the words directly when messages arrive and that's it. We can sum the number of words in the chats for a given period, but this will only be an approximation. Alternatively, we have to add a new field to the region model that explicitly tracks the budget spent on chats.