can receive from signald groupv2, but nothing else

I relied on learning from https://gitlab.com/signald/signald-go but because that project is under GPL and there are no plans on re-licensing (see <https://gitlab.com/signald/signald-go/-/issues/7>) it can't be directly used in matterbridge, which is Apache 2.0

Anyway: as it currently is, this module is crude, probably extremely prone to errors, and nowhere remotely close to stable or production use.
Regardless of that, any help with it would be welcome.

- try to re-subscribe on fail
- list contacts
- use nice contact names instead of phone numbers