Docs setup customizing

[benjaoming]

Sorry about the settings cleanup that went in this PR, but I was kind of looking at settings while writing the docs for them and felt inclined to get these two silly context processors out :)

Fix for #3925

[benjaoming]

Btw. is INLINE_HELP a mature feature yet?

[benjaoming]

I've been working on an idea to allow for a conventional settings module to be located in KALITE_HOME, ~/.kalite/custom_settings.py. This would make instructions for users simpler, make it possible to always put an example file, and UIs would have a place to dump their settings without requiring kalite --settings=some_ui.settings_module which would break off from command line (e.g. you UI customizations to KA Lite would not appear when running kalite from the command line).

[rtibbles]

@benjaoming INLINE_HELP is merged to keep the code in develop, but it is not currently active. The framework is all there, I believe, just needs the 'scripts' for different features.

I believe @tk21 may be generously volunteering some time alongside her full time gig to help us get those implemented over the summer.

[tk21]

@rtibbles Yes, I'm still working on writing the 'scripts' for the different pages -- this is just a matter of appending to the "narratives.yaml" file. There is a bit of error-checking I need to implement, though. Such as only triggering a click on an element after checking that it has been loaded, or something along the lines of that. This affects the tutorials/scripts for which an action is triggered before showing the next tutorial modal.

[benjaoming]

Overruled by #3938.