Review documentation

[jbreue16]

We recently added many new features to CADET; The corresponding documentation should undergo an additional review.

• radial flow doc review: end of modelling section of GRM, LRM, LRMP and interface at interface/unit_operations/radial_flow_models.html
• mct doc review at modelling/unit_operations/multi_channel_transport_model.html and interface/unit_operations/multi_channel_transport_model.html
• Michaelis Menten kinetics at modelling/reaction/michaelis_menten_kinetics.html#michaelis-menten-kinetics-model and interface/reaction/michaelis_menten_kinetics.html
• Updated citation guidelines, see Update and unify citation guidelines #325
• Add Affinity Energy Distribution isotherm and Rate Constant Distribution theory to the documentation #295

PR #327 can be used to commit changes. Changes can be double checked on the documentation branch of the webpage, here