Add support for modules (#4999)

* Add support for modules

* Use "" for inclusion

* Fix missing includes on Poco.Data module

* Add PDF and SevenZip modules, and match modules to build macros

* Add CI test

* Add missing link libraries in CMake

* Add remaining libraries DNSSD, CppParser and CppUnit. Changed some static declarations to inline to export

* We also need to forward the ENABLE_NETSSL_* macros

* Update CMakeLists files

* Add samples as requested, with DateTime and URI test for example

* Fix POCO_MODULES_INSTALL macro

* chore(CMake): Combine install macro for libraries and C++ modules into one macro.

* Apply testsuite changes and address include directories concerns

* Restore accidentally deleted build files

* Mistakenly added a file generated by CMake, removed.

---------

Co-authored-by: Matej Kenda <matejken@gmail.com>

modules/Poco/SevenZip.cppm

@@ -0,0 +1,28 @@
+//
+// SevenZip.cppm
+//
+// C++ module file
+//
+// Copyright (c) 2025, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+module;
+
+#ifdef ENABLE_SEVENZIP
+#include "Poco/SevenZip/Archive.h"
+#include "Poco/SevenZip/ArchiveEntry.h"
+#include "Poco/SevenZip/SevenZip.h"
+#endif
+
+export module Poco.SevenZip;
+
+export namespace Poco::SevenZip {
+	#ifdef ENABLE_SEVENZIP
+	using Poco::SevenZip::Archive;
+	using Poco::SevenZip::ArchiveEntry;
+	using Poco::SevenZip::ArchiveImpl;
+	#endif
+}