OAK-11568 Elastic: improved compatibility for aggregation definitions

[thomasmueller]

• Analyzer configuration is now lenient, quite similar to the Lucene index behavior. This will allow converting Lucene indexes to Elasticsearch. Warnings are logged where needed.
• This PR also removes unused code, and reduces compiler warnings.
• The tests in ElasticIndexHelperTest are about problems trying to load files that are not configured (IllegalStateException etc.)
• The tests in FullTextAnalyzerCommonTest are about compatibility problems
• With the NGram Tokenizer (not filter), behaviour is different between Elastic and Lucene for one case: if the query contains multiple words, the result is found with Lucene, but not with Elastic.

[github-actions]

Commit-Check ✔️

[sonarqubecloud]

Quality Gate passed

Issues
10 New issues
0 Accepted issues

Measures
0 Security Hotspots
87.3% Coverage on New Code
0.0% Duplication on New Code

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