Move Conda packaging chapter to the end of the course

[Scottan]

See discussion in: #26

Move to the end so it doesn't disrupt flow. Can be an optional part of the course if there is time at the end of the day

[andrewgait]

As this will change the numbering system of the chapters, my suggestion is that this happens after we have completed all the other issues we talked about this morning / added to the backlog today, so I'm going to move it to Blocked for now.

[Scottan]

Just making a note on something I spotted that will need following up.

At the start of Chapter 6, we have:

Following the conda lesson, we install the astropy library using:

conda install astropy

I think this can be removed if we are using the jupyter server, but needs double checking.

There will need to be a link or something early on in the course to help those using the notes from a local computer outside the course to be able to install all of the packages sensibly.

[Scottan]

Also further down in chapter 6:

Pint can be installed using conda (and the conda-forge channel):

conda install -c conda-forge pint