temp/eg25-manager: GNSS assistance support, sync with modem-power, etc.

Apply the following patches until upstream merges them all:

• Clean up modem_iface if ModemManager disappear: https://gitlab.com/mobian1/devices/eg25-manager/-/commit/705950bb399781a291a3998014f916fc1effce16
• Synchronize configuration with modem-power: https://gitlab.com/mobian1/devices/eg25-manager/-/merge_requests/18
• GNSS assistance support: https://gitlab.com/mobian1/devices/eg25-manager/-/merge_requests/15

The custom eg25-manager configs we shipped are replaced by the GNSS assistance patch for now. Once we setup a mirror at pmOS for the GNSS assistance data, we can ship custom configs again to set the default URL to the pmOS mirror. This avoids phoning home to Qualcomm.

I run this patch for several weeks already without any problem, GNSS lock is way faster!

💡 When more people test this change and as soon as it is merged and released upstream, this package is upstreamed again to Alpine.