Better Error Handling and Logging

Summary

Better error handling (less exceptions, more error codes) and logging (for more detailed error handling and configuration issues).

Issue: https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/390

See also the tests in caosdb-cppinttest!2 (merged)

Focus

• The TransactionStatus class represents the current status of a Transaction instance.
• The TransactionCode is a numeric representation of the status and intended for c-compatible error handling.
• Messages and Message classes handle the errors, warnings and info messages that come from the server.
• Logging: The logging can be configured via a json file. Otherwise the default configuration is in place.
• A lot of code was moved in order to comply with -pedantic flag. Don't waste your time

Test Environment

Unit tests should run as described in README_SETUP

Integration tests should run against a linkahead in the f-grpc branch

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

README_SETUP.md

@@ -8,7 +8,8 @@
 
 We use [cmake](https://cmake.org) as build tool.
 
-1. `mkdir build && cd build/`
+0. clone/update the subrepo `git submodule update --init proto`
+1. `mkdir build && cd build`
 2. `conan install .. -s "compiler.libcxx=libstdc++11"`
 3. `cmake -B . ..`
 4. `cmake --build .`
@@ -38,6 +39,7 @@ variable.
 We use [Visual Studio 2019](https://visualstudio.microsoft.com/de/vs/features/cplusplus/)
 as compiler. We use [cmake](https://cmake.org/download/) as build tool.
 
+0. clone/update the subrepo `git submodule update --init proto`
 1. `mkdir build`
 2. `cd build`
 3. `conan install .. -g visual_studio -s arch=x86_64 -s build_type=Release -s compiler.toolset=v142 -s compiler.version=16 -s compiler.runtime=MD  --build=missing --update`
@@ -46,6 +48,23 @@ as compiler. We use [cmake](https://cmake.org/download/) as build tool.
    and build the project. (You can open Tools/Command Line/Developer Command
    Prompt and execute `msbuild libcaosdb.sln /property:Configuration=Release`)
 
+### Creating a Local Conan Build ##
+
+Building and installing libcaosdb with Conan is just a single command:  
+`conan create . -s "compiler.libcxx=libstdc++11"`
+
+For MacOS, you probably should adjust the option as mentioned above.
+
+### Troubleshooting
+
+#### `conan install` Fails Due to Missing Prebuilts
+
+When `conan install` fails during the installation of the dependencies because
+a precompiled package is not available for your specific settings, try adding
+the `--build=missing` option: `conan install .. [ other options
+] --build=missing`. This should download and compile the sources of the
+dependencies.
+
 ## Unit Tests
 
 ### Build