Write out BNS inertial centers for control system

[knelli2]

Proposed changes

Now also writes out the inertial centers of the BNS from the control system along with the grid centers

Upgrade instructions

The grid centers of the BNS are now located in the /ControlSystems/BnsGridCenters subfile of the reductions H5 file, and the inertial centers are in the /ControlSystems/BnsInertialCenters subfile.

Code review checklist

• The code is documented and the documentation renders correctly. Run
  make doc to generate the documentation locally into BUILD_DIR/docs/html.
  Then open index.html.
• The code follows the stylistic and code quality guidelines listed in the
  code review guide.
• The PR lists upgrade instructions and is labeled bugfix or
  new feature if appropriate.

Further comments

[nilsdeppe]

LGTM, one suggestion. You can squash immediately.

[nilsdeppe]

Could you add an ASSERT(block_logical_coords.size() == 2, ..)? This would just help with making line 318 clearer. It should be true given only 2 things ever enter into the coords, but would ease readability, I think.

[nilsdeppe]

CI failure is random timeout