CE-1951: Convert useUserNames

Tickets: CE-2078, CE-2082, CE-2095, CE-2097, CE-2100

I found that a couple of api calls aren't in use, so I removed them. Named below:

• useHostList & unpackHostList
• useAvailableHost
• useUserNames & unpackUserList
• useIOCStatistics & unpackIOCStatistics
• useDeployedIOCStatistics & unpackDeployedIOCStat