GUI, Real time job: add support for scan parameters

For specular simulations, GUI real time view does not allow us to modify wavelength, nor any other scan parameter. Under Specular Instrument > Beam, there is only Intensity.

added GUI essential functionality labels

mentioned in merge request !995 (merged)

added wait for dependency! label

marked this issue as related to #621 (closed)

added linked to meta label

marked this issue as related to #974 (closed)

changed milestone to %post-22-cleanup

marked this issue as related to #567 (closed)

mentioned in merge request !2866 (merged)

mentioned in commit e6d93c83

closed with merge request !2866 (merged)