Tof uncertainty threshold per component

[nvaytet]

Instead of having a single number for the threshold in time-of-flight uncertainty that applies to mask the entire lookup table, we now have one number per beamline Component.

The LookupTableRelativeErrorThreshold is now a dict that contains a mapping from component name to threshold value.
For example, in the case of Dream, this could be something like

wf[LookupTableRelativeErrorThreshold] = {
    "mantle": 0.02,
    "endcap_forward": 0.02,
    "endcap_backward": 0.02,
    "high_resolution": 0.02,
    "monitor_cave": 0.05,
    "monitor_bunker": 1.0,
}

We use the NeXusDetectorName and the NeXusName[MonitorType] to get values from the dict.

I set the default to be a defaultdict that returns Inf if the requested key is not found. I don't know if this is a good idea or not.