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/components/LobbyPlayerView.ts

@@ -1,7 +1,6 @@
 import { LitElement, html } from "lit";
 import { customElement, property, state } from "lit/decorators.js";
 import { repeat } from "lit/directives/repeat.js";
-import { PastelTheme } from "../../core/configuration/PastelTheme";
 import {
   ColoredTeams,
   Duos,
@@ -17,6 +16,8 @@ import { assignTeamsLobbyPreview } from "../../core/game/TeamAssignment";
 import { UserSettings } from "../../core/game/UserSettings";
 import { ClientInfo, TeamCountConfig } from "../../core/Schemas";
 import { createRandomName, formatPlayerDisplayName } from "../../core/Util";
+import { Theme } from "../theme/Theme";
+import { themeProvider } from "../theme/ThemeProvider";
 import { getTranslatedPlayerTeamLabel, translateText } from "../Utils";
 
 export interface TeamPreviewData {
@@ -37,7 +38,9 @@ export class LobbyTeamView extends LitElement {
   @property({ type: Number }) nationCount: number = 0;
   @property({ type: Boolean }) isPublicGame: boolean = false;
 
-  private theme: PastelTheme = new PastelTheme();
+  private get theme(): Theme {
+    return themeProvider.current();
+  }
   @state() private showTeamColors: boolean = false;
   private userSettings: UserSettings = new UserSettings();