modem: add versions to all headers

Versions for specific modem modules don't include versions in their
headers, and the chat module did not even define a group.

This commits updates most modem modules to include versions in
their headers. Specifically, the following modules have their
versions set to 1.0.0, as these should no longer be marked
experimental:

- modem_chat
- modem_cmux
- modem_pipe
- modem_pipelink
- modem_ppp
- modem_ubx

Though the modem_ubx was recently refactored, it is tested in CI
and is implemented by two drivers, and has been present since
release 3.7, so it is not marked as experimental.

Signed-off-by: Bjarki Arge Andreasen <bjarki.andreasen@nordicsemi.no>