Refs #9213. Move all the Muon files to separate directory
Refs #9213. Initial data loading classes
Refs #9213. The basic presenter/view interaction for data loading
Refs #9213. Simplest loading implementation
Refs #9213. Better naming for the method and class
Refs #9213. Initial widget view implementation
Refs #9213. Split the step code into multiple files
Refs #9213. Hide presenter inside the mock view

We shouldn't ever access it directly, but rather test it
through the mock view, so better hide it.
Refs #9213. Display data as a plot
Refs #9213. A few UI improvements
Refs #9213. Quick fix for the PlotAsymmetryByLogValue

Child algorithms don't put workspaces to the ADS, unless these
workspaces are group. That's why it wasn't working property for
non-period runs. Will test that propertly in a different ticket.
Refs #9213. Classes for the baseline modelling step
Refs #9213. Basic fitting implementation
Refs #9213. Initial widget view implementation
Refs #9213. Basic step view switching
Refs #9213. Minor code/documentation clean-up
Refs #9213. Transfer loaded data to baseline modelling
Refs #9213. Use MWRunFiles to select first/last run
Refs #9213. Change the way presenter is created

Creating it from view isn't the best approach - the view shouldn't
really be aware of who is controlling it. Additionally, in order to
interfact with the presenter, we should retrieve it from the view each
time.

Some other minor code clean-up was done as well.
Refs #9213. Display baseline-subtracted (corrected) data