INSTETC: allow inverting the value passed to BUMP_STOPS, load in cmd file in twincat ioc

[rerpha]

As someone who uses a Beckhoff I would like my bump strips signal to be correctly propagated to IBEX.

Firstly, these aren't loaded in from twincat, but are from galil, so we should load them in from both (and assume only one will be used)
Secondly, when testing on LARMOR, the signals are the wrong way round, as in tripped is 0 and not tripped is 1, rather than changing this motion logic I want to be able to invert the value and send it to MOT:BUMP_STOPS

Acceptance Criteria

What is the acceptance criteria?

• INSTETC is changed to load in bumpstop.cmd from twincat\ as well as galil\
• a way of inverting the value send to MOT:BUMP_STOPS is given, through a calcout or similar

Extra Information

This could be done with a macro in the same way that the PV name is passed to INSTETC via bumpstops.cmd.

A workaround will be added in custom_records.db on LARMOR for now so that should be removed when this is deployed - this will be done in #6966

[rerpha]

in case we need to patch this on instruments I have made ISISComputingGroup/EPICS-ioc#668 for the first point of the acceptance criteria

[rerpha]

no longer really an issue as we can quite easily just flip this PV in motorextensions loaded in by TC