Feature/Move theme system from core to client-side ThemeProvider (#4108)

**Add approved & assigned issue number here:** 

Resolves #2549

## Description:

Themes are purely for the client's rendering, and the server doesn't
need context on them. This PR moves `Theme.ts` from
`src/core/configuration` to `src/client/theme` and moves affiliation
colors to `render-settings.json`.

This is to support the ability to add additional themes more quickly,
such as colorblind-friendly themes. No visible changes occur from this
refactor.

## 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

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

jetaviz

---------

Co-authored-by: Josh Harris <josh@wickedsick.com>

src/client/render/gl/RenderSettings.ts

@@ -79,6 +79,27 @@ export interface RenderSettings {
     defensePostRange: number;
     embargoTintRatio: number;
     friendlyTintRatio: number;
+    embargoTintR: number;
+    embargoTintG: number;
+    embargoTintB: number;
+    friendlyTintR: number;
+    friendlyTintG: number;
+    friendlyTintB: number;
+  };
+  /** Alt-view affiliation colors (0–1 RGB). */
+  affiliation: {
+    selfR: number;
+    selfG: number;
+    selfB: number;
+    allyR: number;
+    allyG: number;
+    allyB: number;
+    neutralR: number;
+    neutralG: number;
+    neutralB: number;
+    enemyR: number;
+    enemyG: number;
+    enemyB: number;
   };
   railroad: {
     railMinZoom: number;