Improve documentation to include npm steps.

Problem/Motivation

I installed the module using composer and after enabling it I couldn't see any of the modules information on the browse page. When I checked the console, I saw a few JS-related errors and noticed the module requires a few npm commands to be run before it can be used. It would be nice to include these 2 commands in the README file.

npm install
npm run build

As a developer, it didn't take much time to figure this out, but this can be an issue for some other users. Am I missing something here?

Steps to reproduce

Install the module and check the browse page.

Proposed resolution

Add npm commands to README file.

Remaining tasks

• ✅ File an issue about this project
• ☐ Addition/Change/Update/Fix to this project
• ☐ Testing to ensure no regression
• ☐ Automated unit/functional testing coverage
• ☐ Developer Documentation support on feature change/addition
• ☐ User Guide Documentation support on feature change/addition
• ☐ Code review from 1 Drupal core team member
• ☐ Full testing and approval
• ☐ Credit contributors
• ☐ Review with the product owner
• ☐ Release

User interface changes

API changes

Data model changes

Release notes snippet