updates sandbox component 'opennlp-similarity' to be compatible with latest opennlp-tools release (#71)

- adjusts opennlp-tools to 2.1.0
- adjusts parent project (org.apache.apache) to version 18
- adjusts Java language level to 11
- updates several dependencies to more up-to-date versions to mitigate several CVEs
- removes binary version of `jverbnet` from the lib folder in exchange for the most recent, maven managed version of this dependency
- adjusts code to changes in various dependencies
- adjusts some array declarations to comply with Java, not C style
- adapts codebase to work with Solr & Lucene version 8.11.x
- fixes existing JUnit tests
- removes all binary dep jars from 'lib' folder - all managed via Maven now
- adds TODOs and related Jira issue number for some spots discussed in related PR #71
- kicks out "Auto-generated catch block" comments
- removes unused imports
92 files changed