If `kiwix-serve` is run with the `--nosearchbar` option the toolbar is
disabled (hidden) in its viewer.
Note however that certain actions performed by the viewer merely with
the purpose of keeping the toolbar up-to-date are still carried out.
Auto hiding of the toolbars on narrow screens works only for the first
page loaded in the viewer. Navigating to other pages interferes with
autohiding as follows:
- If the toolbar was hidden, it stays hidden.
- If the toolbar was not hidden, it loses the ability to autohide.
Made the viewer respect the `--blockexternal` and `--nolibrarybutton`
options of `kiwix-serve`. Those options are passed to the viewer
via the dynamically generated resource `/viewer_settings.js`.
Before this fix there were two issues with the taskbar search box:
1. The book used for the suggestions API was resolved only once during
the page load and didn't change during navigation.
2. The current book could not be resolved from a search URL.
Now both issues are fixed.