future-proof Nightwatch for bokeh v3

[sybenzvi]

Current versions of Nightwatch at KPNO and NERSC are using bokeh 2.4. The current bokeh release (Aug. 2023) is bokeh 3.2.

Bokeh made a number of disruptive changes to the API in v3 that will break many Nightwatch features, including obnoxious changes like alterations to the names of keyword arguments deep inside function calls.

We need to begin adapting a number of calls to bokeh classes and functions prior to migrating to bokeh v3. The changes may be significant enough to require a new Nightwatch major release.