Improve UI performance for systems with large number of cameras

**Describe what you are trying to accomplish and why in non technical terms**
I want to fix slow browser performance when loading/updating these pages on systems with excessive cameras.

**Describe the solution you'd like**
Making these pages have tabs with a max of 20 cameras ie.

**Describe alternatives you've considered**
Obviously on Live I generally use camera groups that has the same effect and works perfectly, but have included it as I feel it's warranted for 'All Cameras' as default page that's loaded and in case of system using the bottom right alerts instead.

**Additional context**
Especially the system one is an extreme use case as I have right now 150+ cameras, just thought worth posting as maybe useful for slower machines on reasonable setups.

Start by reproducing the slow loading and updating behavior on the All Cameras and system pages with a setup containing 150+ cameras. Trace the relevant UI entry points and compare performance before and after grouping cameras into tabs with no more than 20 cameras each, including the bottom-right alerts use case.

Written by the indexing model from the issue text.