Improve file_helper implementation

[sdvendramini]

The implementation should be improved by separating, for each target (FileIO and Filesystem), the functions that are purely wrappers from those that add logic.

This can be done as follows:

../common/file_helper/
├── CMakeLists.txt
├── file_io
│   ├── include
│   │   ├── file_io_utils.hpp
│   │   ├── file_io_wrapper.hpp
│   │   ├── ifile_io_utils.hpp
│   │   └── ifile_io_wrapper.hpp
│   ├── src
│   │   ├── file_io_utils.cpp
│   │   └── file_io_wrapper.cpp
│   └── tests
│       ├── CMakeLists.txt
│       ├── file_io_utils_test.cpp
│       ├── file_io_wrapper_test.cpp
│       └── mocks
│           ├── file_io_utils.hpp
│           └── file_io_wrapper.hpp
└── filesystem
    ├── include
    │   ├── filesystem_utils.hpp
    │   ├── filesystem_wrapper.hpp
    │   ├── ifilesystem_utils.hpp
    │   └── ifilesystem_wrapper.hpp
    ├── src
    │   ├── filesystem_utils.cpp
    │   └── filesystem_wrapper.cpp
    └── tests
        ├── CMakeLists.txt
		├── filesystem_utils_test.cpp
        ├── filesystem_wrapper_test.cpp
        └── mocks
            ├── mock_filesystem_utils.hpp
        	└── mock_filesystem_wrapper.hpp

This approach makes the code more modular, allowing file_helper functions that contain logic to be tested using the same library's wrapper mocks, thus avoiding duplicate mocks.

Keep in mind that there are some files where filesystem_wrapper functions might be used, such as in file_op.c. Adding the necessary wrappers (e.g., FileSize, w_copy_file, etc.).

The implementation of tests that manipulate the real filesystem should be improved by using these mocks, for example in the instance_handler tests and filesystem_wrapper tests.