NIMROD: fix camera homing

[rerpha]

When setting up the motion setpoints + getting in/out positions for #6932 we decided to start off by homing (which was working last time we looked at it) but for some reason the Galil stopped on the upper limit and then didn't move anymore. This was solved by tweaking/jogging/sending a move but homing now does not finish. This may be related to #6631 as it uses the same homing routine currently.

Acceptance Criteria

What is the acceptance criteria?

• Some time is booked with JN to investigate homing
• Cause for this behaviour is found and written somewhere useful on the wiki
• NIMROD camera is able to be homed again

Extra Information

We could try just using the forward limit homing routine rather than the routine that is currently used (forward limit + find index negative) but it's unusual that it just stopped working.

[KathrynBaker]

Consider homing to reverse limit (home out of the beam not into the beam)

[rerpha]

• Nimrod homing routine changed from forwardlimFIneg to Reverselim (out of beam!)
• offset applied so motionsetpoints still work - Outbeam is also home location
• runcontrol applied on Outofbeam (inpos-for-Outbeam block) by scientists request

Whilst there we helped with some scripts and found a pylint exception (jack will create a new ticket for this, though looks to be a bug in pylint itself)

Scientists are happy with this after a demo so again not much to review here!

[LowriJenkins]

If the scientists are happy with this, I'll be happy to put this to review complete once Jack has made a ticket for the exception.

[LowriJenkins]

Ticket for pylint error is above.