feat: add Datadog Go, .NET, and PHP providers - #1440

Changed pages include:

• index.html - view
• 404.html - view
• blog/index.html - view
• community/index.html - view
• ecosystem/index.html - view
• search/index.html - view
• specification/index.html - view
• support-training/index.html - view
• blog/andre-silva-spotlight/index.html - view
• blog/announcing-angular-sdk/index.html - view

There are more changes not included in the list