Stop using deprecated Solr features

Solr deprecated some features in version 7.0.0 that will be removed completely in a later version, like 8.0.0.
Example warnings when executed with our current `schema.xml` and Solr 7.7 (from [this comment](https://github.com/JanusGraph/janusgraph/pull/1567#discussion_r283349430)):

```bash
Solr loaded a deprecated plugin/analysis class [solr.TrieIntField]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.TrieFloatField]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.TrieLongField]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.TrieDoubleField]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.TrieDateField]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.SynonymFilterFactory]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.WordDelimiterFilterFactory]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.LatLonType]. Please consult documentation how to replace it accordingly.
Solr loaded a deprecated plugin/analysis class [solr.CurrencyField]. Please consult documentation how to replace it accordingly.
Replace 'com.spatial4j.core' with 'org.locationtech.spatial4j' in your schema.
```

Start with the repository's current schema.xml and compare its field and filter definitions with the Solr 7.7 deprecation warnings listed here. Check Solr replacement guidance for the Trie, synonym, word-delimiter, spatial, currency, and spatial4j entries. Done means the schema no longer emits these warnings while preserving the existing search behavior.

Written by the indexing model from the issue text.