Ucloud-sdk-python2

ENHANCEMENT:

- Improve documentation: add response fields and models to service documentation (3)

BUGFIX:

- Fix transport keywork arguments has no-effected error, add user-agent to default headers (3)

FEATURES:

- add new product `PathX` (1)
- add new product `UAccount` (1)
- add new product `UDB` (1)
- add new product `UDisk` (1)
- add new product `UDPN` (1)
- add new product `UHost` (1)
- add new product `ULB` (1)
- add new product `UMem` (1)
- add new product `UNet` (1)
- add new product `UPHost` (1)
- add new product `VPC` (1)