use eg25-manager for modem on pinephone

This is a WIP MR. I intend to upstream eg25-manager to Alpine, but included it here so folks could help test.

TODO:

• make openrc init script for eg25-manager
• test lots of suspend/resumes + phone calls/SMS
• add device package changes to install eg25-manager when MM is installed
• add device package changes to install old eg25 init script when ofono is installed
• merge https://gitlab.com/postmarketOS/pmaports/-/merge_requests/1825 (not required, but it does improve reliability)
• upstream eg25-manager package (https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/16120)
• fix gps (it's broken on master too, but it should at least work when using eg25-manager since the init will likely be different)