chore: remove yarn.lock and restore rc files

We currently use two packagers: npm and yarn. This is bad, and I thus propose to switch to npm.

Furthermore, in the vite PR we removed some .*rc files, which does not seem nessescary as far as I understand,
and it would be better to keep them.

.babelrc

@@ -0,0 +1,34 @@
+{
+  "presets": [
+    "@babel/preset-env",
+    "@babel/preset-react"
+  ],
+  "plugins": [
+    "@babel/plugin-syntax-dynamic-import",
+    "@babel/plugin-syntax-import-meta",
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-proposal-json-strings",
+    [
+      "@babel/plugin-proposal-decorators",
+      {
+        "legacy": true
+      }
+    ],
+    "@babel/plugin-proposal-function-sent",
+    "@babel/plugin-proposal-export-namespace-from",
+    "@babel/plugin-proposal-numeric-separator",
+    "@babel/plugin-proposal-throw-expressions",
+    "@babel/plugin-proposal-export-default-from",
+    "@babel/plugin-proposal-logical-assignment-operators",
+    "@babel/plugin-proposal-optional-chaining",
+    [
+      "@babel/plugin-proposal-pipeline-operator",
+      {
+        "proposal": "minimal"
+      }
+    ],
+    "@babel/plugin-proposal-nullish-coalescing-operator",
+    "@babel/plugin-proposal-do-expressions",
+    "@babel/plugin-proposal-function-bind"
+  ]
+}

.eslintrc

@@ -0,0 +1,23 @@
+{
+  "parserOptions": {
+    "ecmaFeatures": {
+      "jsx": true,
+      "modules": true
+    }
+  },
+  "env": {
+    "browser": true,
+    "node": true
+  },
+  "parser": "babel-eslint",
+  "rules": {
+    "quotes": [2, "single"],
+    "strict": [2, "never"],
+    "react/jsx-uses-react": 2,
+    "react/jsx-uses-vars": 2,
+    "react/react-in-jsx-scope": 2
+  },
+  "plugins": [
+    "react"
+  ]
+}

.jshintrc

@@ -0,0 +1,6 @@
+{
+  "node": true,
+  "browser": true,
+  "esnext": true,
+  "newcap": false
+}