Risky finite difference in eeI Jastrow evalGradSource

**Is your feature request related to a problem? Please describe.**
Finite difference implementation complicates the code. It may cause unexpected side effect since it naturally changes the states of the wavefunction and breaks const assumptions. It is also susceptible to numerical issues especially when a node crossing is involved.
It is also not performant due to redundant calculations.

**Describe the solution you'd like**
Implement analytic derivatives.