Useless code should be deleted in LCAO

[dyzheng]

Describe the Code Quality Issue

In class LCAO_Hamilt, some functions are not used now:

calculate_STN_R_sparse_for_S

In clase Gint_K, some functions are not used now:

cal_vlocal_R_sparseMatrix

Additional Context

No response

Task list for Issue attackers (only for developers)

• Identify the specific code file or section with the code quality issue.
• Investigate the issue and determine the root cause.
• Research best practices and potential solutions for the identified issue.
• Refactor the code to improve code quality, following the suggested solution.
• Ensure the refactored code adheres to the project's coding standards.
• Test the refactored code to ensure it functions as expected.
• Update any relevant documentation, if necessary.
• Submit a pull request with the refactored code and a description of the changes made.