switch to a more flexible variant description format

The new format combines compound splitting and abbreviation.
It also allows to restrict rules to additional conditions
(like language or region). This latter ability is not used
yet.

test/python/test_tokenizer_legacy_icu.py

@@ -60,13 +60,12 @@ def analyzer(tokenizer_factory, test_config, monkeypatch,
     monkeypatch.undo()
 
     def _mk_analyser(norm=("[[:Punctuation:][:Space:]]+ > ' '",), trans=(':: upper()',),
-                     suffixes=('gasse', ), abbr=('street => st', )):
+                     variants=('~gasse -> gasse', 'street => st', )):
         cfgfile = tmp_path / 'analyser_test_config.yaml'
         with cfgfile.open('w') as stream:
             cfgstr = {'normalization' : list(norm),
                        'transliteration' : list(trans),
-                       'compound_suffixes' : list(suffixes),
-                       'abbreviations' : list(abbr)}
+                       'variants' : [ {'words': list(variants)}]}
             yaml.dump(cfgstr, stream)
         tok.naming_rules = ICUNameProcessorRules(loader=ICURuleLoader(cfgfile))