Add vcpkg support

Summary

While exploring vcpkg I realized that with Conan 2 it should be possible to actually offer both Conan and vcpkg as package managers. This MR brings support for compilation with vcpkg to the cpplib.

Related to #81 (closed)

Focus

• A few files were added to support vcpkg, and some changes had to be made to the CMakeLists.txt file to make it compatible with both Conan 2 and vcpkg.
• Instructions on how to build with vcpkg can be found in docs/Install_develop.rst.
• A GitLab CI step to test building with vcpkg was added to the pipeline.

Test Environment

Follow new build instructions to test vcpkg.

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doc/Install_develop.rst

@@ -22,7 +22,7 @@ which have ``make`` installed, type this in your command line terminal:
 Building with ``vcpkg``
 ~~~~~~~~~~~~~~~~~~~~~~~
 
-You can use the vcpkg package manager to install the dependencies (`vcpkg.json`). It's included as 
+Instead of Conan, you can use the vcpkg package manager to install the dependencies (`vcpkg.json`). It's included as 
 a submodule in the project. To install the dependencies, run the following commands:
 
 .. code:: console
@@ -31,12 +31,19 @@ a submodule in the project. To install the dependencies, run the following comma
    vcpkg/vcpkg install
 
 
+Copy the ``grpc-cpp-plugin`` to the build directory (TODO: This should ideally be done automatically by CMake): 
+
+.. code:: console
+
+   mkdir -p build/build_tools
+   cp vcpkg_installed/<os>/tools/grpc/grpc_cpp_plugin build/build_tools
+
 Then compile the project with CMake by including the vcpkg toolchain file:
 
 .. code:: console
 
    cd build
-   cmake -S .. -B . -DCMAKE_TOOLCHAIN_FILE=../vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-linux 
+   cmake -S .. -B . -DCMAKE_TOOLCHAIN_FILE=../vcpkg/scripts/buildsystems/vcpkg.cmake -DVCPKG_TARGET_TRIPLET=x64-linux -DCMAKE_BUILD_TYPE=Release
    cmake --build .
 
 
@@ -49,7 +56,7 @@ package manager. The compiler must support the C++17 standard.
 1. clone/update the subrepo ``git submodule update --init proto``
 2. ``conan install . -s build_type=Release --build=missing``
 3. ``cd build/Release``
-4. ``cmake .``
+4. ``cmake -S ../.. -G "Unix Makefiles" -DCMAKE_TOOLCHAIN_FILE=generators/conan_toolchain.cmake  -DCMAKE_POLICY_DEFAULT_CMP0091=NEW -DCMAKE_BUILD_TYPE=Release``
 5. ``cmake --build .``
 
 You may also want to install libcaosdb system-wide to