Add the popup for contextual help (#322)

Also:
- add modal component
- add CloseButton component
12 jobs for dev in 8 minutes and 22 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test Build Static
passed #249703
Test_N_Build

00:06:12

passed #249704
Test_N_Build:internal

00:06:19

 
  Build Docker Images
passed #249707
Nginx:Internal-EHK

00:01:33

passed #249708
Nginx:Internal-WP

00:01:33

passed #249705
Nginx:Staging-EHK

00:01:40

passed #249706
Nginx:Staging-WP

00:01:33

 
  Deploy
passed #249712
Internal:EHK-HH

00:00:14

passed #249714
Internal:WP-HH

00:00:12

passed #249713
Internal:WP-HX

00:00:13

passed #249709
Staging:EHK-HH

00:00:13

passed #249711
Staging:WP-HH

00:00:13

passed #249710
Staging:WP-HX

00:00:15