(refs #31) add below info on Host
- datastore name
- datastore disk capacity (byte)
- datastore disk free space (byte)
remove duplicate import
update a hosts mock file
update a guest mock, adding 3 fields below.
- ip
- host
- vmwareToolsStatus
 1. NotInstalled : not yet installed
 2. Installed : already installed latest  version
 3. ToBeUpdated : already installed old version, it should be updated to latest version
Merge pull request #38 from chidakiyo/feature/display_esxi_disk_space

Feature/display esxi disk space