[PHP-WEBMASTER] [web-php] PR #1284: Add PHP History Timeline

[mkurzeja]

Pull Request: https://github.com/php/web-php/pull/1284
Author: mkurzeja

Initial implementation of #1265

This adds two main changes:

1. New view of PHP History Timeline as a separate page. Events are loaded from 
a .json file

![image](https://github.com/user-attachments/assets/3a087510-f05c-4999-8fd4-d69605128f61)

https://drop.accesto.com/v/f0cATp

2. Adds link to the new page to the right side menu:
![image](https://github.com/user-attachments/assets/75f6e27b-4cff-4f22-9530-6ec28cf3cedd)


Events from years 2020-2025 are not included in this PR, I will create a 
separate one.