[ACS-7462] cleanup deprecated api for DataTable and DocumentList

[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?

• deprecate unused and untested gallery mode for document list and datatable (ACS-7462)
• remove unused interface (ACS-7460)
• remove unused DataTable.iconAltTextKey method
• remove unused DataTable.getSortingKey method (part of gallery UI)
• update documentation for DataTable - bug fixes, typo fixes, example fixes

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:

[MichalKinas]

Just one question, should we add a comment somewhere to indicate that the gallery mode won't be available anymore since next version?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud