ui: add dark mode to see Quay in a new light or lack thereof (PROJQUAY-6570)

[dmesser]

I bring you dark mode.

Why? Because staring at a bright screen is like staring at the sun. Not cool.

This introduces:

• Theme selector: choice is king, we are not dictators
• Dark mode: easy on the eyes, hard on the boring
• Auto mode: reflects your desktop's snazzy dark mode setting
• Menu menu: refactored to use MenuContainer, MenuToggle and Menu with icons like the PatternFly gods intended
• Persistent choice: browser crashed because too many tabs open? the UI remembers your theme selection, courtesy of local storage

Like sunglasses for your screen. See for yourself:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (94735bc) 70.59% compared to head (7060b6a) 70.59%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2575   +/-   ##
=======================================
  Coverage   70.59%   70.59%           
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  Files         434      434           
  Lines       39856    39856           
  Branches     5166     5166           
=======================================
  Hits        28135    28135           
- Misses      10102    10104    +2     
+ Partials     1619     1617    -2     

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unit	70.59% <ø> (ø)

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[BillDett]

sweet

[Sunandadadi]

The PR looks great, one minor comment - can we change tool tip for auto-them to device-based theme instead of browser-based-theme. Browser can be confused with the web browser but in reality it reflects device's mode.

[dmesser]

@Sunandadadi done

[Sunandadadi]

lgtm