Add iterm relax cutoff to UI

[IvoFPV]

Adds iterm relax cutoff to PID tuning tab of the configurator. Requires addition to MSP which will go with this PR.

[IvoFPV]

Fixed msp packet order and added hiding of the setting for older firmware versions.

[Docteh]

Doesn't quite look good for smaller screens

How about the span get told to not wrap lines? the spans themselves still get line-wrapped.

.tab-pid_tuning table.compensation .suboption {
    margin-left: 4%;
    white-space: nowrap;
}