Update connectome-constrained vision code to work with the first official release of FlyVision

[sibocw]

There is now an official release of FlyVision: see https://github.com/TuragaLab/flyvis and https://turagalab.github.io/flyvis/.

Janne told me that they'll soon publish it on PyPI. Once they do, we should:

1. Adapt our code to work with their most recent version.
2. Get rid of our FlyVision fork and use a version-locked copy from PyPI. (Recall that as a temporary solution, we made a fork of FlyVision and used this fork to have a stabilized main branch).
3. Update relevant documentation re. FlyVision installation accordingly. This includes at least the "(Optional) Additional dependencies for provided tutorials and examples" box on https://neuromechfly.org/installation.html.

I'm assigning this to myself, unless @tkclam wants to help out.

Copying @lappalainenj.