gluon-web-cellular: add auth option to GUI

[T0biii]

this should fixes #2750 by adding a dropdown menu for the auth methods.

atm it is untested, but we believe that this can be tested soon by someone from ffmuc.

More Infos: https://openwrt.org/docs/guide-user/network/wan/wwan/ltedongle#qmi_protocol_configuration_parameters

[AiyionPrime]

atm it is untested

Could we wait for the test report prior merging?

[seilpforte]

I just tested this, works fine.

root@ff-router:~# uci show | grep cellular
firewall.@zone[1].network='wan' 'wan6' 'cellular_4' 'cellular_6'
gluon.cellular=cellular
gluon.cellular.enabled='1'
gluon.cellular.apn='internet.eplus.de'
gluon.cellular.username='eplus'
gluon.cellular.pdptype='IPV4V6'
gluon.cellular.pin='1234'
gluon.cellular.password='internet'
gluon.cellular.auth='chap'
network.cellular=interface
network.cellular.proto='qmi'
network.cellular.disabled='0'
network.cellular.device='/dev/cdc-wdm0'
network.cellular.peerdns='0'
network.cellular.apn='internet.eplus.de'
network.cellular.pdptype='IPV4V6'
network.cellular.ipv6='auto'
network.cellular.pincode='1234'
network.cellular.username='eplus'
network.cellular.password='internet'
network.cellular.auth='chap'
network.cellular.delay='15'

[T0biii]

habe die vorgeschlagenen Änderungen direkt noch hinzugefügt :)