feat(svgGraph): show Y axis in short format

with M, k, K and other abbrs

time: 0h:25
feat(ajax): delay and queue for a loader

show a loader after 500ms after request
hide only if a queue is empty
other features

time: 1h:10
style(theme): add styles to the dark theme

add styles;
separate css files;

time: 2h:15