Re-enable linting and codecov mechanisms

[ohltyler]

#108 disabled the lint workflow to have ongoing development still have fully passing PRs and tracking main/2.x branches. Before this is released and before the plugin becomes more stable, this should be re-enabled to enforce lint checking on PRs and merges to main/2.x.

UPDATE: the PR was closed as this was disabled from github itself. details in referenced PR. This can be re-enabled the same way, at which time we can close this issue.

Additional linting mechanisms to re-enable:

1. pre-commit configuration:
   In package.json, add:

  "pre-commit": [
    "lint:es:precommit"
  ],

2. pre-commit dependency:
   add this in devDependencies:

  "devDependencies": {
    "pre-commit": "^1.2.2"
  },

3. pre-commit script
   add this script under scripts in package.json:

    "lint:es:precommit": "yarn lint:es common/* public/* server/*",

4. Re-enable pre-commit hooks in .git/hooks in the repository

5. Re-enable codecov. Details of it being disabled in Parse and persist UI metadata on editor page #125

[ohltyler]

Setting 2.15 as a target goal to have this workflow re-enabled.

[ohltyler]

UPDATE: below details added in issue description

---

Additionally, pre-commit configuration should be added back, to enable linting on every commit by default. It was removed due to lint violations during rapid development and the fatigue of constantly adding --no-verify when committing:

In package.json, add:

  "pre-commit": [
    "lint:es:precommit"
  ],

add this in devDependencies:

  "devDependencies": {
    "pre-commit": "^1.2.2"
  },
```,

add this script:

"lint:es:precommit": "yarn lint:es common/* public/* server/*",

re-enable pre-commit hooks in `.git/hooks` in the repository