feat: Add ZeroMQ support for DFTracer

[izzet]

• Updated CMakeLists.txt to include ZeroMQ and cppzmq dependencies based on the writer type.
• Introduced DFTRACER_WRITER_TYPE_ENV constant for environment variable configuration.
• Refactored metadata handling to use MetadataMap type instead of std::unordered_map.
• Enhanced DFTracer and DFTLogger classes to accommodate new metadata structure.
• Implemented ZeroMQWriter class for sending log messages over ZeroMQ.
• Created a base WriterBase class to standardize logging interfaces for different writers.
• Updated ChromeWriter to utilize the new base class and refactored JSON conversion methods.
• Added configuration management for writer type selection via environment variables.

[Copilot]

Pull Request Overview

This PR introduces ZeroMQ support for DFTracer along with a refactoring of logging writers to inherit from a new WriterBase interface and use a unified MetadataMap type for metadata management. Key changes include the addition of the ZeroMQWriter class, updates to configuration management and build files for ZeroMQ dependencies, and refactoring of ChromeWriter, DFLogger, and DFTracerCore to use the new metadata and writer type configuration.

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/dftracer/writer/zeromq_writer.cpp	Adds ZeroMQWriter implementation and integrates ZeroMQ logging functionality.
src/dftracer/writer/writer_base.h	Introduces a common base class for logging writers.
src/dftracer/writer/writer_base.cpp	Implements shared JSON conversion functions for events and metadata.
src/dftracer/writer/chrome_writer.{h,cpp}	Refactors ChromeWriter to inherit from WriterBase and adapt to MetadataMap.
src/dftracer/utils/configuration_manager.{h,cpp}	Adds writer_type configuration via environment variables.
src/dftracer/{dftracer.cpp,df_logger.h,core/dftracer_main.{h,cpp}}	Updates to use MetadataMap for metadata handling.
include/dftracer/core/typedef.h	Defines MetadataMap as a type alias for metadata handling.
CMakeLists.txt and related cmake modules/configure files	Update dependencies and build configuration for ZeroMQ support.

Comments suppressed due to low confidence (1)

src/dftracer/writer/chrome_writer.cpp:60

• [nitpick] The initialization and subsequent update of 'is_first_write' seems inconsistent with its intended use for formatting; please verify that the starting value and update logic correctly reflect the expected behavior for the first log entry.

is_first_write = false;

[izzet]

Addresses #78