Let web views configure if they need to show a bcv control

[Sebastian-ubs]

User Story
As a user I do not want to see bcv controls in uis that are not related to scripture (e.g. settings, about, registry, s/r, ...) so that I am not confused.

Description
Give web views an option to show a bcv control or not.
Might be decided in roadmap#15 if to show a toolbar and how it should look in these cases.

Interestingly the current settings uis don't have it, so there seems to be a way...?

Implementation idea
up to you

Testing ideas

[tjcouch-sil]

Note: the settings dialogs are in core, so they are not web views. That's why they don't have this.

I recommend we consider what options we want to give web views for configuring their "tab nav" once we have a "final" UX design (I have seen some designs, but I have always heard they are not done yet) before taking on any issues related to showing or hiding certain things on the tab nav. That way, we will make a good design that will last instead of making something that will get deprecated or completely break immediately because we didn't have the whole picture in view. We don't have to wait, but that's my preference and recommendation.

[Sebastian-ubs]

ux case is https://github.com/paranext/ux/issues/181