Feature : printing initial charge density

[wenfei-li]

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[WHUweiqingzhou]

@wenfei-li,
I notice this PR has not been updated for while, any help needed?

[wenfei-li]

@wenfei-li, I notice this PR has not been updated for while, any help needed?

This pr is finished work. I do not think it needs any further update or modification.

[mohanchen]

The developer won't follow instructions, but I will merge it. P. S. Further modifications of this PR by other developers will be expected.