improve the swagger page for mainnet

[romeo4934]

• fix the title --> IOV Name Service Rest API

• only display endpoint which is relevant for mainnet (cash, info, usernames/owner, usernames/iovstarname)

• for the cash/balances endpoint

  • instead of 'Returns a bnsd/username.Token entitiies" ' you should say
    "returns balances based on iov address"

• for the username/orkun*iov endpoint

  • you should say "Resolve an iov starname'

• for the username/owner endpoint

  • you should say "Returns the list of iov starname owned by this iov address"

• fix the Models section