Refactor OpenVINO backend: move and clean up parameter handling

[zhaixuejun1993]

This pull request refactors how model inputs and extra inputs are handled in the GGML-to-OpenVINO translation layer, improving type safety and code clarity. Instead of storing model inputs and extra inputs as generic OpenVINO nodes, the code now uses explicit structures (ModelInputInfo and ModelExtraInputInfo) to describe their properties. This change also centralizes the logic for creating OpenVINO parameters and constants, and updates related interfaces and usages throughout the codebase. Additionally, the codebase is cleaned up with improved documentation and removal of unused utilities.

Key changes:

Refactoring of Model Input Handling:

• Replaces storage of model inputs and extra inputs from std::shared_ptr<ov::Node> to new structures ModelInputInfo and ModelExtraInputInfo, providing explicit type and shape information. (ggml-decoder.h, openvino/decoder.h, ggml-decoder.cpp, [1] [2] [3] [4] [5] [6] [7]

• Updates the get_model_inputs() and get_model_extra_inputs() interfaces to return the new info structures, and removes the now-unnecessary get_model_extra_input_values() method. (ggml-decoder.h, openvino/decoder.h, [1] [2]

Centralized Parameter and Constant Creation:

• Introduces helper functions create_parameter and create_extra_input to consistently create OpenVINO parameter and constant nodes from the new info structures. Updates the translation session to use these helpers when constructing the OpenVINO model. (openvino/translate_session.cpp, [1] [2]

API and Utility Improvements:

• Updates get_ov_input_tensor to use the new ModelExtraInputInfo structure for constructing input tensors. (utils.cpp, ggml/src/ggml-openvino/utils.cppL840-R843)
• Adds or improves documentation for several utility functions and classes, making the codebase easier to understand and maintain. (openvino/translate_session.h, openvino/utils.h, [1] [2] [3]

Cleanup and Removal of Unused Code:

• Removes unused or redundant utility functions such as getCurrentTime, non_cont_dim, and various template utilities from utils.cpp and utils.h. (utils.cpp, utils.h, [1] [2]

Minor Fixes:

• Fixes a function call in mulmat.cpp to use the correct input processing function. (mulmat.cpp, ggml/src/ggml-openvino/openvino/op/mulmat.cppL36-R37)
• Removes an unused OpenVINO header include. (ggml-decoder.cpp, ggml/src/ggml-openvino/ggml-decoder.cppL28)## Overview

Additional information

Requirements

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