Change empire name in exported timelapse to medium white on black for readability

[chennin]

I find the current text color (almost the same as the empire fill color) to be hard to read. This takes a small part of #80 that isn't related to empire colors. It changes the empire name text on the timelapse export to a medium-size white with black outline. I found that the most readable, although I'm slightly sad to not be using the empire color in the text.

Image: https://i.imgur.com/1JIGcej.gif (wait til 2246)

Here is a comparison of several options considered: https://imgur.com/a/shYAEMS

[eliasdoehne]

Yea I guess it's hard to ensure readability when the empire colors can be very dark or very bright. I'm ok with the change, maybe we can reconsider this later once we use the in-game colors for empires