Settings: Add hotspot setting to allow VPN upstreams

    <!-- Hostname setting -->

    <string name="device_hostname">Device hostname</string>

    <!-- Hotspot lineage extras -->

    <string name="tethering_allow_vpn_upstreams_title">Allow clients to use VPNs</string>

    <string name="tethering_allow_vpn_upstreams_summary">Permit hotspot clients to use this device\u2019s VPN connections for upstream connectivity</string>

    <!-- Lock screen cover art -->

    <string name="lockscreen_media_art_title">Display media cover art</string>

        android:summary="@string/bluetooth_tethering_subtext"

        settings:keywords="@string/keywords_hotspot_tethering" />

    <lineageos.preference.LineageSecureSettingSwitchPreference

        android:key="tethering_allow_vpn_upstreams"

        android:title="@string/tethering_allow_vpn_upstreams_title"

        android:summary="@string/tethering_allow_vpn_upstreams_summary"

        android:defaultValue="false" />

    <Preference

        android:key="disabled_on_data_saver"

        android:summary="@string/tether_settings_disabled_on_data_saver"