Need subspace diagonalization without scc

[Cstandardlib]

Background

#5463
When using DiagH_subspace in cg method, we construct an overlap matrix scc by default.
This can be a huge burden on memory.

Initial psi set is not orthogonal

However, in cg we do orthogonalization, so that psi set becomes diagonal after a cg loop, and we will call DiagH_subspace to actually solve
a standard eigenproblem since scc is identity:

Describe the solution you'd like

So we may need a wrapper of standard eigensolver.
Will it be faster?

Task list only for developers

• Notice possible changes of behavior
• Explain the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi

Notice Possible Changes of Behavior (Reminder only for developers)

No response

Notice any changes of core modules (Reminder only for developers)

No response

Notice Possible Changes of Core Modules (Reminder only for developers)

No response

Additional Context

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Task list for Issue attackers (only for developers)

• Review and understand the proposed feature and its importance.
• Research on the existing solutions and relevant research articles/resources.
• Discuss with the team to evaluate the feasibility of implementing the feature.
• Create a design document outlining the proposed solution and implementation details.
• Get feedback from the team on the design document.
• Develop the feature following the agreed design.
• Write unit tests and integration tests for the feature.
• Update the documentation to include the new feature.
• Perform code review and address any issues.
• Merge the feature into the main branch.
• Monitor for any issues or bugs reported by users after the feature is released.
• Address any issues or bugs reported by users and continuously improve the feature.

[dyzheng]

I admit that calculating scc is a step that can be skipped in the cg diagonalization process, but the description of the memory burden is incorrect.
I think hpsi and spsi shared memory in this function.