Add support for versioned expire timers

[GranPC]

See whisperfish/libsignal-service-rs#321 for more details

NB: my Rust skills compare unfavorably to those of an amoeba, and as such it is entirely possible I have done something horribly wrong.

[Schmiddiii]

@GranPC Seems like you forgot to update the Cargo.toml to point to the newest commit of libsignal-service-rs, and rebuild presage (to update Cargo.lock).

[GranPC]

@Schmiddiii yeah, that wasn't possible when I originally created the PR because the libsignal-service-rs commit wasn't merged yet. Will get to it in a sec.

[gferon]

Thanks a lot for the PR! I introduced a function to make sure the logic is shared when sending both direct and group messages. I also realized there are a bunch of other issues unrelated to your changes: I'm pretty sure we can add a field to the groups_v2::Timer struct of libsignal-service-rs since it has most likely been introduced in the Protobuf messages.