IqtFit algorithm

[mantid-builder]

This issue was originally TRAC 8907

They both do very similar things, but FuryFitMult uses a multi domain function instead. We can combine most of the functionality and make the output of the parameters table more consistent.

Part of the issue with this is that multi domain functions cannot be converted to a function string from the C++ API. Roman has a ticket to fix this as part of #10094.

Ideally they should be converted to a single algorithm that has the option to do an individual or sequential fit.

[mantid-builder]

@NickDraper (2014-02-14T11:07:55):
bulk move to assigned at the into of the triage step

[ElliotAOram]

This is being completed in #15094 and this issue can be closed once the changes are merged