Better dashboard

[eug3nix]

The monitoring dashboard needs several improvements:
Widget responsiveness: widget card layout breaks when window size is too small.

Time series graph readability:
Use colors which we already have in pgmanage css palettes. Use thicker lines (2px), use background fills for areas under the line.
Time axis labels can be displayed less frequently to de-clutter the UI (each 2nd label could be hidden for example). When there are many labels they
get rotated to fit the widget width, ideally we should limit rotation to 45 degrees or vertical, so that labels on different widgets look uniform.
Align timestamp labels to some standard time-chunks like 1\4th of a minute or so.
Limit the amount of datapoints displayed in the widget, maybe with a moving window function so that the last N minutes are only visible.

Get rid of single statistic widgets or change them to display more useful info in a single widget. A good example is "In recovery" widget which displays a single boolean value and occupies 1\4th of visible screen space.

Revise "grid" graphs, remove unnecessary columns. For example, the activity graph has a lot of information, part of which is not needed.

Improve widget management modal layout: move visibility checkbox to the rightmost column, change it to toggle switch