Setup CI

• linting with pre-commit & prettier
• build on CI

Closes #7 (closed)

Requires #6 (closed)

.eslintrc.js

-module.exports = {
-  root: true,
-  env: {
-    node: true,
-    webextensions: true,
-  },
-  extends: ["plugin:vue/essential", "eslint:recommended", "@vue/prettier"],
-  parserOptions: {
-    parser: "babel-eslint",
-  },
-  rules: {
-    "no-console": process.env.NODE_ENV === "production" ? "warn" : "off",
-    "no-debugger": process.env.NODE_ENV === "production" ? "warn" : "off",
-  },
-};