Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

The PR addresses the following improvements:

1.Improving member functions:

• Renaming read_from_io and write_to_io to more descriptive names for better clarity.
• Enhancing documentation for these functions to make their purpose, inputs, outputs, and edge-case handling explicit.

2.RFC Refactoring functions into the base class with the following considerations (subject to undone):

• This change allows decoders currently with m_buf_supported = false to potentially use these functions in the future to support buffer reading.
• Introducing the m_f variable in the base class, which potentially enables efficient handling of file streams by reducing redundant file-opening operations. For example, the source file can be assigned to m_f once when the decoder is selected, avoiding the need to reopen the file in readHeader().