Major plugin refactor and cleanup.

Switched to POCO library for unified platform/library interface.
Deprecated the external module API. It was creating more problems than solving.
Removed most built-in libraries in favor of system libraries for easier maintenance.
Cleaned and secured code with help from static analyzers.

vendor/POCO/ApacheConnector/CMakeLists.txt

@@ -0,0 +1,26 @@
+# Sources
+file(GLOB SRCS_G "src/*.cpp")
+POCO_SOURCES_AUTO(SRCS ${SRCS_G})
+
+# Headers
+file(GLOB_RECURSE HDRS_G "include/*.h")
+POCO_HEADERS_AUTO(SRCS ${HDRS_G})
+
+add_library(mod_poco SHARED ${SRCS})
+set_target_properties(mod_poco
+	PROPERTIES
+	VERSION ${SHARED_LIBRARY_VERSION} SOVERSION ${SHARED_LIBRARY_VERSION}
+	DEFINE_SYMBOL ApacheHandlers_EXPORTS)
+target_include_directories(mod_poco
+	PUBLIC
+		$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+		$<INSTALL_INTERFACE:include>
+	PRIVATE
+		${APACHE2_INCLUDE_DIRS}
+		${CMAKE_CURRENT_SOURCE_DIR}/src
+)
+target_link_libraries(mod_poco PUBLIC Poco::Util Poco::Net Apache::Apr Apache::Aprutil)
+
+if(ENABLE_TESTS)
+	add_subdirectory(samples)
+endif()