mpegtsparse: Add split-on-rai option

The following discussion from !972 (merged) should be addressed:

• @ndufresne started a discussion: (+5 comments)

  I second @tpm. I think you should keep up to adding alignment property, with default to auto/0. Then adding strict alignment should be in its own patch, and possibly its own MR which woukd effectively depend on this one. But the remaining here is non controversial, fixes a bug and could be candidate to backport (though arguably, this adds an API, but we could split adding that property to solve that too). The patch division is mostly for the ability to backport the bug fix part of this MR.

  While for the strict-alignment, I would like to discuss further the naming. The property name is miss-adapted. We should instead have a property name that express the fact it will split out buffer when the random_access_indicator (as named in the spec) is met, otherwise follow the configured alignment. A consequence is that you'll have to mass rename it in the code too.