Segmenter constructor options/preferences normalization

[sffc]

In #3284 we decided to add a content_locale option to segmenter.

In #5839, @zbraniecki asked some questions about the signature of the constructors.

Currently we have constructors of the following shape:

1. new: singleton static data (infallible), no content locale tailorings
2. try_new_unstable: dynamic data, no content locale tailorings
3. try_new_with_options: static data with content locale tailorings
4. try_new_with_options_unstable: dynamic data with content locale tailorings

Which of the following should we do?

1. Keep all 4 sets of constructors listed above
2. Remove constructor sets 1 and 2. Rename 3 and 4 to not have with_options.
3. Remove constructor set 2. Rename 3 and 4 to not have with_options. Keep constructor 1 as a compiled data infallible optimization.

And, should we take a LanguageIdentifier or a preferences bag for the content locale? (Please understand the discussion in #3284 before stating an opinion on this)

@zbraniecki @makotokato @aethanyc @Manishearth