Add ESlint VS Code installation instructions

### Dependency
- [x] https://github.com/hackforla/website/issues/4101
- [x] prioritization of Roll Out Plan for ESLint implementation (after spelling issues are resolved)

### Overview
As developers of the Hack for LA website, we want to align on the tools we're using to keep the codebase as free as possible of coding errors so our reputation and the quality of our code is maintained. For this issue, we will add installation instructions for the VS Code extension, ESLint, so our developers will be aligned on the local spellchecker used.

### Action Items
- [ ] In `CONTRIBUTING.md`, update the Table of Contents to include linkage to the ESLint installation process with the following:
```
- [**1.7.a Setup ESLint**](#17a-setup-eslint)
```

- [ ] In the same file, add the following instructions for the installation process:
```
#### **1.7.a Setup ESLint**

You must use VS Code as your local text editor to install the VS Code extension for linting your codebase, ESLint.

The recommended installation method is to install ESLint directly from the VS Code text editor, and those instructions can be found [here](https://code.visualstudio.com/learn/get-started/extensions). The extension can also be installed via the VS Code Marketplace website [here](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint). Feel free to reach out in the [Hack for LA Slack channel](https://hackforla.slack.com/messages/hfla-site/) if you have trouble installing the extension in VS Code.
```

- [ ] Ensure that the linkage from the first action item links correctly to the second action item's instructions.

### Resources/Instructions

- [ESLint VS Code extension](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint)
- [Installing VS Code extensions](https://code.visualstudio.com/learn/get-started/extensions)
- [CONTRIBUTING.md](https://github.com/hackforla/website/blob/gh-pages/CONTRIBUTING.md)