- AudioEncoders take as input a list of buffers instead of a single one;

- New class: AudioBuffer, expected to be removed from the TTS modules;
- AudioEncoders return a Guava's optional instead of null strings;
- Updated the versions in the BOM.
the framework BoM (imported by the `audio-modules-parent` already declares Guava's version. If you do not rely on a specific version, please use the shared version instead (i.e. do not declare the version here).