Muon Fitting Refactor - Implement Normal Fitting

[robertapplin]

Description of work. This PR creates the basic and general fitting widgets which can be used for normal fitting in the fitting tab of Muon Analysis and FDA interfaces. At this point, only normal fitting is possible.

Tests have been added for:

• [x] FitControlsView
• [x] FitFunctionOptionsView
• [x] BasicFittingView
• [x] BasicFittingPresenter
• [x] BasicFittingModel
• [x] GeneralFittingOptionsView
• [x] GeneralFittingView
• [x] GeneralFittingPresenter
• [x] GeneralFittingModel.
• [x] FittingTabPresenterTest and FittingTabModelTest have been removed.

Things that will be done in future PRs:

• TF Asymmetry fitting
• Make the Sequential Fitting tab work with the new models.

To test: Code review and test.

Reviewer

Please comment on the following (full description):

Code Review

• Is the code of an acceptable quality?
• Does the code conform to the coding standards?
• Are the unit tests small and test the class in isolation?
• If there is GUI work does it follow the GUI standards?
• If there are changes in the release notes then do they describe the changes appropriately?

Functional Tests

• Do changes function as described? Add comments below that describe the tests performed?
• Do the changes handle unexpected situations, e.g. bad input?
• Has the relevant (user and developer) documentation been added/updated?

Does everything look good? Mark the review as Approve. A member of @mantidproject/gatekeepers will take care of it.