fix(graph): fix for when data min/max delta is zero and negative and grid y min/max is auto, fixes #6980

Polish on icon placement, incorporated torkel's better idea for going slightly lighter, make sure error icon color was white now

Softened the color a bit by mixing in the panel-bg, so it's not introducing any new variables. Was too start as pure body-bg

got reports on twitter about broken links.

fixes #6473

feat(panel): working on panel help text and unifying panel links, panel errors, and panel help into a single panel feature, #4079 , #6847

feat(panel): working on panel help text and unifying panel links, panel errors, and panel help into a single panel feature, #4079 , #6847

closes #6676

closes #6905

closes #6866

ref #6949