Fix compilation errors on Windows

Summary

Resolves #34 (closed), #75 (closed) and #85 (closed).

Focus

Windows compatibility has been brought to a point where in Release build mode, caosdb.dll, ccaosdb.dll and the test CLI clients build without errors. The clients are also able to start (function was not tested yet). To achieve this a few changes were necessary:

• The GRPC_GENERATED sources have to be added to the ccaosdb library. Just linking is not enough on Windows (see #90 (closed)). This should not and does not seem to have an impact on the Linux build.
• The splitting of the GRPC_GENERATED from the main library for the Debug/Test was removed as it does not work on Windows (see #90 (closed)) and does not provide any advantage on Linux.
• Linking to stdc++fs for using has been removed. This was only necessary for gcc<9.1.
• Retrieving the HOME folder on Windows was added in include/caosdb/utility.h (enabled/disabled via a macro)

Note that there is not yet a pipeline for Windows. Unit tests are anyway not yet functional (see #90 (closed)).

Test Environment

Follow build instructions for Windows.

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doc/CHANGELOG.md

@@ -26,6 +26,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Values can now hold empty vectors and do not silently convert them into a scalar.
+- [indiscale#34](https://gitlab.indiscale.com/caosdb/src/caosdb-cpplib/-/issues/34)
+  Building shared libraries on Windows.
 
 ### Security