US69000: Adding extra fields for external volume import

[achu-1612]

Description:

Adding extra fields support for external volume import-

• CapacityUsed
• UnmanagedVolume
• ActiveSite
• CreatedSite
• ReplicationEnabled

Testing:

• I updated the metal client after these changes were made, in the quake vendor repo.
• Created a volume
• I edited the db recorded to populate random data for the newly added fields in the volume model.
• I used the /v1 API to test whether those fields were getting fetched.
  

[mchuang3]

NOTE: requires https://github.com/hpe-hcss/quake/pull/4713

[chitranm]

NOTE: requires hpe-hcss/quake#4713

I have merged the model changes PR.