Utilize workbox-window for service worker registration

[westonruter]

• Fixes Make use of Workbox window to register service worker and provide access to registration #204. Service worker registration is available at wp.serviceWorkerWindow at the document's DOMContentLoaded event.
• Discontinue registering the service worker for the admin on the frontend when the user is logged-in. The service worker is installed when the user goes to the login screen already.
• Fixes Eliminate custom skipWaiting message in favor of de facto Workbox message #444. When wp_service_worker_skip_waiting is filtered false in PHP, service worker installation waiting can be skipped via wp.serviceWorkerWindow.messageSkipWaiting(). See Workbox docs.
• Deprecates wp_disable_script_concatenation() since admin service worker is not caching admin assets since WP_Service_Worker_Admin_Assets_Integration is not enabled by default (and it is deprecated per Deprecate integrations #403). As part of this the wordpress_sw_installed cookie is no longer set when the admin SW is installed.
• Use module script instead of text/javascript for SW installation on frontend. This incidentally prevents JS errors IE11 which doesn't understand JS modules. Fixes Backward Compatibility for IE11 #227.

[codecov-commenter]

Codecov Report

Merging #578 (56f1611) into develop (714d850) will decrease coverage by 0.02%.
The diff coverage is 0.00%.

@@              Coverage Diff              @@
##             develop     #578      +/-   ##
=============================================
- Coverage      17.28%   17.25%   -0.03%     
  Complexity       296      296              
=============================================
  Files             55       56       +1     
  Lines           1770     1773       +3     
=============================================
  Hits             306      306              
- Misses          1464     1467       +3     

Flag	Coverage Δ
php	17.25% <0.00%> (-0.03%)	⬇️
unit	17.25% <0.00%> (-0.03%)	⬇️

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Impacted Files	Coverage Δ
wp-includes/default-filters.php	0.00% <ø> (ø)
wp-includes/deprecated.php	0.00% <0.00%> (ø)
wp-includes/service-workers.php	22.00% <0.00%> (+0.84%)	⬆️

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[amedina]

LGTM.