Add flags for the Arctic map (#3610)

## Description:

Adds flags of all canadian provinces and territories (except quebec
which was already in), and the flags of the Soviet Republics, Tannu tuva
and the Far Eastern Republic. These are flags for nations of the Arctic
map, a different PR will be made so that the nations in the map use
these flags if added. Also makes flags usable.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tri.star1011

CREDITS.md

@@ -88,3 +88,8 @@ Noah Petro (NASA/GSFC) ORCID logo.
 Stats icon by [Meko](https://thenounproject.com/mekoda/) – https://thenounproject.com/icon/stats-4942475/
 Pay Per Click icon by [Fauzan Adiima](https://thenounproject.com/creator/fauzan94/) – https://thenounproject.com/icon/pay-per-click-2586454/
 Medal icon by [Snow](https://thenounproject.com/snowdoll/) – https://thenounproject.com/icon/medal-4567887/
+
+### Flags
+
+[Wikimedia Commons](https://commons.wikimedia.org/wiki/Flag)
+Licensed under [CC BY-SA 3.0 DE](https://creativecommons.org/licenses/by-sa/3.0/de/deed.en)