Write a plan for mirrors alignment on I05

At this point in the alignment, we already have nice parameters for the dependence of
m3mj6_x, but we want to establish the dependence of m3mj6_pitch vs m1es_pitch.

The GDA scan command would be something like:

`scan m1es_pitch -200 1600 75 m3mj6_pitch 4750 5350 8 waittime 0.1 dj7current_new`

We then need to fit the peak at each value of m1es_pitch, and from the peak positions
we fit a third order polynomial. Polynomial coefficients constants will then be readjusted.
With m1es_pitch then well established, we subsequently do the focusing scan using the gas cell.

This scan actually takes over an hour, because the step motion of the hexapod
(m3mj6_pitch) is slow. In principle we could try to do it in a "fly" mode
with bluesky, which could be a significant speed up.