Add Affinity Energy Distribution isotherm and Rate Constant Distribution theory to the document

[WFlynnZ]

Here we add documentations for the Affinity Energy Distribution (AED) isotherm and Rate Constant Distribution (RCD) theory. Both equations are integral equations and need to be discretized before solving them numerically. However, the discretized equation can already be solved in CADET based on other previous isotherm and reaction implementations. Therefore, the task is to simply add documents.

• add docs for the AED
• add docs for the RCD

Specially, if one is only interested in obtaining an AED from the experimental isotherm data, a specialized algorithm called Expectation Maximization (EM) method is available to solve the inverse problem. The EM method is an iterative method based on simple algebraic operations and is independent on other functionalities of CADET. For it to be part of the CADET family, we need a dedicated simple module that can be called by the user.

• add EM method

[jbreue16]

Hi Flynn, thanks for starting this.
The EM method should probably be an individual PR so that the update of the documentation can be merged quickly.