Accessibility bug fixes

[gingi]

Several other improvements:

• Systemic application of red asterisks for required fields (input directive only set it as a read-only property that did not honor validations or explicit required HTML attributes)
• Localization of several components
• Replacement of some custom colors with theme colors
• Corrected internal spelling of several classes, files, and directories

Most visible change is the removal of the light gray background of the square icon buttons.

Old:

New:

[codecov]

Codecov Report

Merging #2629 (5cef89a) into master (ee1f66d) will increase coverage by 0.01%.
The diff coverage is 76.74%.

❗ Current head 5cef89a differs from pull request most recent head 87c2a34. Consider uploading reports for the commit 87c2a34 to get more accurate results

@@            Coverage Diff             @@
##           master    #2629      +/-   ##
==========================================
+ Coverage   65.08%   65.09%   +0.01%     
==========================================
  Files         916      916              
  Lines       26420    26454      +34     
  Branches     5214     5230      +16     
==========================================
+ Hits        17195    17221      +26     
- Misses       9225     9233       +8     

Impacted Files	Coverage Δ
src/@batch-flask/ui/dropdown/dropdown.module.ts	100.00% <ø> (ø)
...batch-flask/ui/server-error/server-error.module.ts	100.00% <ø> (ø)
src/@batch-flask/ui/sidebar/sidebar.module.ts	100.00% <ø> (ø)
.../app/components/account/action/account-commands.ts	34.21% <0.00%> (ø)
...ing-started-card/getting-started-card.component.ts	23.07% <0.00%> (ø)
...-picker/aad-app-picker/aad-app-picker.component.ts	16.66% <ø> (ø)
...p-secret-picker/aad-app-secret-picker.component.ts	21.87% <ø> (ø)
...entials-picker/aad-credentials-picker.component.ts	19.14% <ø> (ø)
...create-new-aad-app/create-new-aad-app.component.ts	19.29% <ø> (ø)
...ad-app-secret/generate-aad-app-secret.component.ts	31.25% <ø> (ø)
... and 8 more

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[cRui861]

Fixes #2634