V5 compatibility with v4

[RSamaium]

Purpose of the Added Code

The code introduced in this pull request adds a new ViteJS plugin whose main purpose is to ensure compatibility between RPGJS v4 and RPGJS v5.

RPGJS v4 relies on a specific project structure and build behavior that does not work the same way in Vite 5. Since RPGJS v5 is built on a different engine and workflow, some features and conventions from v4 are no longer supported out of the box.

The new plugin re-implements the expected v4-style project structure and behavior on top of the v5 architecture, allowing existing projects to migrate gradually or to maintain compatibility with both versions.

Below is an example of how the plugin is meant to be used:

import { defineConfig } from 'vite';
import { compatibilityV4Plugin, rpgjs } from '@rpgjs/vite';
import path from 'path';

export default defineConfig({
    plugins: [
        compatibilityV4Plugin(),
        ...rpgjs(),
    ],
    resolve: {
        alias: {
            '@': path.resolve(__dirname, './src')
        }
    },
    server: {
        port: 3000
    }
});

The plugin also supports Tiled by default.
However, for Tiled map files to be correctly detected, they must be placed inside a tiled directory at the root of the project.