Documentation: Create PHP documentation on https://glide.valkey.io/

[prateek-kumar-improving]

Cleanup all documentation for PHP and move all documentation to https://glide.valkey.io/
Tasks:

• Quick start, initial setup, add pull request template - PHP: update quickstart guide valkey-glide-docs#131
• Basic operations, Architecture, Command API, Quick start - PHP: Add Quickstart, Basic operations, architecture, command API section valkey-glide-docs#134
• Add all core features sections - PHP: Add Core features section valkey-glide-docs#135
• Add Migration guide for PHP Redis - PHP: Add migration guide section valkey-glide-docs#148
• Add troubleshooting section - Add PHP troubleshooting section valkey-glide-docs#139
• Add how to guide - PHP: Add how to section valkey-glide-docs#158
• Add references section - PHP: Add reference section valkey-glide-docs#160
• Add Valkey scripting commands - PHP: Add reference section valkey-glide-docs#160