Do not use proxy when querying cloud metadata from APM agents

[SylvainJuge]

Description

Ensure that agents do not use a proxy when querying cloud metadata, even if the application is configured to use an HTTP proxy.

Specification change: #785

• Already implemented in Java with Bypass proxy for cloud metadata apm-agent-java#3108

Agent Issues

• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-dotnet#2053
• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-nodejs#3277
• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-python#1806
• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-go#1415
• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-php#921
• [META 786] Do not use proxy when querying cloud metadata from APM agents apm-agent-ruby#1384