New Feature: Count the amount of translated characters per session/week/month.

[simbleau]

In an attempt to be transparent to the user and help them avoid being inconspicuously charged by Google for exceeding the free allotment of translated characters per month, it would be helpful to display this information to the user in the panel.

I'm not sure if Google can relay this information, or whether we could store this information in a hidden RuneLite config. This is low priority for now.