docs: fix quick start link

[jboix]

Description

• Fixes all the links to the quick start guide of pillarbox-web.
• Makes the homepage point to the readme file in github for each individual package instead of the demo page for better discoverability.
• Fixes links to contributing guidelines.

Checklist

• [x] I have followed the project's style and contribution guidelines.
• [x] I have performed a self-review of my own changes.
• [x] I have made corresponding changes to the documentation.
• [x] I have added tests that prove my fix is effective or that my feature works.

[github-actions[bot]]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	94.47%	958 / 1014
🔵	Statements	94.47%	958 / 1014
🔵	Functions	94.2%	65 / 69
🔵	Branches	92.23%	95 / 103

File Coverage

No changed files found.

Generated in workflow #86

[github-actions[bot]]

PR Preview Action v1.4.7 :---: Preview removed because the pull request was closed. 2024-07-09 09:10 UTC

[github-actions[bot]]

:tada: This PR is included in version @srgssr/pillarbox-playlist-v1.3.0 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket:

[github-actions[bot]]

:tada: This PR is included in version @srgssr/skip-button-v1.0.3 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: