Layers should sort with oldest on top, newest on bottom

[cynthiamah]

Layer Order
When creating a new layer, it appears at the bottom of the legend but when the browser is refreshed, it goes to the top.

Layers should sort by chronological order of creation date with the oldest on top, and newest on the bottom.

+Add Layer Command should always be visible
The +Add Layer command should always remain at the top of the left panel under the map name. The layer names will scroll.

Focus on newly created layer
When the user creates a new layer, it should appear at the bottom of the layer list and we should scroll to the bottom of the list so that the newly created layer is visible.