improved language picker

[DenysVuika]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (check one with "x")

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation
• Other... Please describe:

What is the current behaviour? (You can also link to an open issue here)

What is the new behaviour?

• migrate language picker button from ACA to ADF
• introduce new Language Service to reduce the logic from the language button/menu components
• simplify the language components
• provide defaults for language service as the officially supported languages
• remove custom languages list from app.config.json as it's based on official defaults (reduces the json size)

Does this PR introduce a breaking change? (check one with "x")

• Yes
• No

If this PR contains a breaking change, please describe the impact and migration path for existing applications: ...

Other information:

[codecov-io]

Codecov Report

Merging #6890 (95e9cde) into develop (37b10ec) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #6890      +/-   ##
===========================================
+ Coverage    76.51%   76.57%   +0.05%     
===========================================
  Files          885      878       -7     
  Lines        20219    19957     -262     
  Branches      4030     3959      -71     
===========================================
- Hits         15471    15282     -189     
+ Misses        3509     3456      -53     
+ Partials      1239     1219      -20     

Impacted Files	Coverage Δ
lib/core/language-menu/language-menu.module.ts	100.00% <ø> (ø)
lib/core/services/user-preferences.service.ts	87.50% <ø> (ø)
lib/core/language-menu/language-menu.component.ts	100.00% <100.00%> (ø)
...ib/core/language-menu/language-picker.component.ts	100.00% <100.00%> (ø)
lib/core/services/language.service.ts	100.00% <100.00%> (ø)
lib/core/services/translate-loader.service.ts	66.12% <0.00%> (-9.68%)	⬇️
...src/lib/document-list/data/share-data-row.model.ts	73.68% <0.00%> (-2.64%)	⬇️
lib/extensions/src/lib/config/extension-utils.ts
...b/extensions/src/lib/evaluators/core.evaluators.ts
lib/extensions/src/test.ts
... and 8 more

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