gdbus: convert doc/network-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/phonebook-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/pushnotification-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/radio-settings-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/sim-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/siri-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/smartmessaging-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/stk-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/supplementaryservices-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/text-telephony-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/voicecall-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>
gdbus: convert doc/voicecallmanager-api.txt

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>