Feature: Supports the calculation of local density of states.

[WHUweiqingzhou]

Background

local density of states is defined by:
$$D(\varepsilon,\mathbf{x})=\sum_{i}f_{i}||\psi(\varepsilon,\mathbf{x})\rangle|^2$$

ABACUS can calculate local density of states to simulate STM image.

Describe the solution you'd like

Supports the calculation of local density of states.

[WHUweiqingzhou]

see #4192.

[kirk0830]

this feature has been implemented by @YuLiu98 in PR #6100, #6109 and #6123