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/Renderer.ts

@@ -478,7 +478,7 @@ export class GPURenderer {
     this.sceneTarget = { fbo: sceneFbo, tex: sceneTex, w: 1, h: 1 };
 
     // --- Alt-view passes ---
-    this.affiliationPalette = new AffiliationPalette(gl);
+    this.affiliationPalette = new AffiliationPalette(gl, this.settings);
     const affTex = this.affiliationPalette.getTexture();
     this.borderStampPass.setAffiliationTex(affTex);
     this.unitPass.setAffiliationTex(affTex);