Independent peoples panel

New tab where we can manage our treatie with independent people.

Now we need to depend on that terrible notification system built in game where we got tons of information about some boring starvation, next level of pollution that change nothing (I usually know that my city is polluted from its smog, not a notification) hidden units travelling your territory 3 times weaker than your militia, and another broken trade that change nearly nothing for you, and you can't even do anything about it. Between this, you can miss some important news about the next treaties that you can sign, and some treaties can change a lot. Also, new independent peoples rises, and you could miss this sweet spot to catch them in grasp of your money and influence to gain theirs trust before others.