Making expandable/collapsible sidebar navigation + navigation depth configurable

[jorisvandenbossche]

Partly addressing #381, in a sense that this makes it easier to turn off the expandable navigation sidebar, and thus you can get back to the behaviour (and performance) of 0.5.2, while having the other enhancements of 0.6.0

[jorisvandenbossche]

It feels a bit strange to say you can turn off the expandable navigation by setting an option to True (and in general "collapse" doesn't necessarily indicate that the actual HTML is trimmed), but "collapse_navigation" is consistent with RTD and consistent with sphinx' own terminology of collapse=True/False

[choldgraf]

Other than a minor nitpick I think this is good to go

[jorisvandenbossche]

Thanks!

[tupui]

Sorry if this is silly, my html skills are basic. But, would it be technically possible to use some JS to link to the common sidebar html files? We could then reduce the size of the individual html files in case of huge sidebars.

[jorisvandenbossche]

@tupui see also my comments at #381 (comment) and #364.
I briefly looked into that, and it turns out not to be that simple. The sidebar HTML on each page differs slightly, (eg the paths in href can be different, different element tagged as "active"), so that would require quite a bit of javascript to update that dynamically.
(but I am certainly interested in seeing improvements here!)

Let's maybe discuss further in #364