Added eslint rule: prefer single quotes when possible, prefer double to escaping

.eslintrc.json

@@ -22,6 +22,7 @@
     "rules": {
         "semi": [2, "always"],
         "no-unused-vars": "off",
-        "@typescript-eslint/no-unused-vars": "error"
+        "@typescript-eslint/no-unused-vars": "error",
+        "quotes": [2, "single", { "avoidEscape": true }]
     }
 }