Initial setup of prettier and eslint

.editorconfig

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+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = true

.eslintrc.js

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+module.exports = {
+  parserOptions: {
+    sourceType: 'module',
+  },
+
+  env: {
+    es2021: true,
+    node: true,
+  },
+
+  extends: ['eslint:recommended', 'plugin:prettier/recommended'],
+
+  overrides: [
+    {
+      files: ['./src/client/**'],
+      parserOptions: {
+        sourceType: 'module',
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+      env: { browser: true, node: false, es2021: true },
+
+      extends: [
+        'eslint:recommended',
+        'plugin:react/recommended',
+        'plugin:prettier/recommended',
+      ],
+
+      plugins: ['react'],
+    },
+    {
+      files: ['./src/server/**'],
+      env: { browser: false, node: true, es2021: true },
+    },
+    {
+      files: ['./src/game/**'],
+      env: { browser: false, node: false, es2021: true },
+    },
+  ],
+};

.prettierrc.js

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+module.exports = {
+  trailingComma: 'all',
+  singleQuote: true,
+};