remove UI elements in ngOnDestroy

[lbdorrou]

Locally I've started adding functionality to remove markers when the component is removed. Needed it for making the map work dynamically with a web socket system. I wasn't sure if this was something on the road map.

[elasticrash]

To be honest, I haven't planned such scenario, my goal was mostly to make every component updatable. But I'll definitely add this on my road map. The bad thing about this project is that I made it for myself, as part of a larger project that I am currently working on so generally its features depends on other needs. But I am trying on my free time to make it as generic and usable as possible.