diffusion dynamics in SYCL

[Xiangyu-Hu]

By introducing variable array and constant array, now the diffusion dynamics can be run on GPU.

The follows are summary generated by copilot:

This pull request includes several changes to improve the codebase by adding new templates and classes, refactoring existing structures, and updating documentation. The most important changes include the addition of new templates for handling pairs and return types, refactoring of constant and variable array classes, and updates to reduce functors and dynamics sequences.

New Templates and Classes:

• src/shared/common/base_data_type.h: Added ZeroData specialization for std::pair to handle pairs of types.
• src/shared/common/common_functors.h: Added ReturnFunction template to define a return type for various functors.
• src/shared/particle_dynamics/base_local_dynamics.h: Added FinalOutput class within BaseLocalDynamicsReduce to handle final output of reduction operations.

Refactoring of Constant and Variable Arrays:

• src/shared/common/sphinxsys_constant.h: Refactored DiscreteConstant and related classes into ConstantArray and DeviceOnlyConstantArray to handle arrays of constants more efficiently.
• src/shared/common/sphinxsys_variable_array.h: Refactored VariableArray and related classes to simplify handling of variable arrays, including adding DeviceOnlyVariableArray. [1] [2]

Updates to Reduce Functors:

• src/shared/particle_dynamics/reduce_functors.h: Refactored reduce functors to use ReturnFunction and added specializations for handling pairs in ReduceSum. [1] [2] [3] [4] [5] [6] [7]

Updates to Dynamics Sequences:

• src/shared/shared_ck/particle_dynamics/complex_algorithms_ck.h: Refactored SequencedCombination to DynamicsSequence to streamline the execution of dynamics sequences.

Documentation and Miscellaneous Updates:

• README.md: Removed outdated information about master and stable branches.
• src/shared/io_system/io_plt.cpp: Minor formatting changes to improve readability.
• src/shared/shared_ck/io_system/io_observation_ck.h: Updated ReducedQuantityRecording to use FinalOutput for deducing variable type. [1] [2]
• src/shared/shared_ck/particle_dynamics/all_shared_physical_dynamics_ck.h: Included diffusion_dynamics_ck.hpp header.