Lamb shift calculation #79

We need to first have a working implementation of the following two types of Lamb shift calculation:

• Implementing the Lamb shift for CGME OpenQuantumBase.jl#49
• Implementing Lamb shift for ULC OpenQuantumBase.jl#61

Then we want to investigate another possible implementation of Lamb shift:

• Add geometric-arithmetic master equation (GAME) #78

We don't need to optimize the implementation for v0.7