Introducing developer mode for the Agent

The latest release (version 5.4) of the Datadog Agent includes profiling tools, known as "developer mode," to improve performance and efficiency. This feature is particularly useful for developers actively working on or contributing to the Datadog Agent code. Developer mode supports various metrics such as CPU usage, memory consumption, threads in use, network connections open, and total time to run configured checks. It can profile individual Agent Checks and enable full developer mode for profiling everything. The collected metrics are available in Datadog under the datadog.agent.* namespace and in collector.log files on Linux or Windows systems.