ZoneMinder upgraded to Bootstrap 4.5

[knight-of-ni]

ZoneMinder uses the Bootstrap toolkit to generate various parts of the ZoneMinder web console.

We just performed a major upgrade from Bootstrap 3 to 4.5, and not everything has been fixed yet. There should not be anything unusable, but if you see something that doesn't look right, please report it here:
https://github.com/ZoneMinder/zoneminder/issues/2991

Looking ahead, this upgrade will allow us to create a new, slimmer navigation bar that doesn't take up so much real estate on the monitor. You will have the option to keep the current, fat navbar if you choose.