Refactor: move snap_psibeta_half_tddft to module_tddft

[jinzx10]

Reminder

• Have you linked an issue with this pull request?
• Have you added adequate unit tests and/or case tests for your pull request?
• Have you noticed possible changes of behavior below or in the linked issue?
• Have you explained the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi? (ignore if not applicable)

Linked Issue

Fix #...

Unit Tests and/or Case Tests for my changes

No.

What's changed?

"snap_psibeta_half_tddft", a former member function of ORB_gen_tables, is found to

• compute <phi_1| exp(-iAr) | phi_2 >, which does not fall into the category of two-center integration;
• adopt a Lebedev-Laikov grid integration algorithm;
• have nothing to do with the class member variables of ORB_gen_tables.

Based on reasons above, it seems that its present location might not be the best option. As part of the clean-up of ORB_gen_tables, this function is moved to module_hamilt_lcao/module_tddft as a standalone function.

Any changes of core modules? (ignore if not applicable)

No.