Implementation considerations

[nciric]

While we aim at a unified API solution in #3 , we should also recognize that different companies could have partial and proprietary solutions they would like to reuse.

ICU already has prior art solving the problem, e.g. transliterator and break iterator.

There are two cases we should consider:

1. User is fine with defaults, uses code & lexicons provided by inflection project
2. User has a better implementation for a set of languages, and overrides defaults for those languages only, The rest falls back on inflection defaults. User solutions can range from pure lexicon lookup, heuristics to ML models for more complex cases.

Inflection code shouldn't depend on user libraries, but it should provide registration APIs where they can hook up their implementation to be used with our APIs.