Provider VDC CRUD

[dataclouder]

• Add methods to retrieve vSphere vCenters
• Add methods to retrieve vSphere resource pools
• Add methods to retrieve network pools
• Fix some non-cumulative queries to get all paginated elements
• Add functions to create, update, and delete a Provider VDC

Testing:
go test -tags 'providervdc vsphere' -check.vv -timeout 0

go test -tags 'providervdc vsphere' -vcd-verbose -check.f TestVCD.Test_ProviderVdcCRUD -check.vv -timeout 0
START: api_vcd_test.go:518: TestVCD.SetUpSuite
Running on VCD https://xxxxxxxx.com/api (version 10.4.0.20079017 built at 2022-07-08 22:20:22 +0000 UTC)
as user administrator@System (using password)
Skipping all vapp tests because one of the following wasn't given: Network, StorageProfile, Catalog, Catalogitem
PASS: api_vcd_test.go:518: TestVCD.SetUpSuite	8.243s

START: provider_vdc_test.go:186: TestVCD.Test_ProviderVdcCRUD
*** ProviderVDC with network pool
  creating provider VDC 'TestVCD.Test_ProviderVdcCRUD' using resource pool 'resource-pool-for-vcd-01' and storage profile '*'
  renaming provider VDC to 'TestNewName'
  renaming back provider VDC to 'TestVCD.Test_ProviderVdcCRUD'
  adding resource pool 'resource-pool-for-vcd-02' to provider VDC
  removing resource pool 'resource-pool-for-vcd-02' from provider VDC
  adding storage profile 'Development2' to provider VDC
  removing storage profile 'Development2' from provider VDC
  disabling provider VDC 'TestVCD.Test_ProviderVdcCRUD'
  removing provider VDC 'TestVCD.Test_ProviderVdcCRUD'
*** ProviderVDC without network pool
  creating provider VDC 'TestVCD.Test_ProviderVdcCRUD' using resource pool 'resource-pool-for-vcd-01' and storage profile '*'
  renaming provider VDC to 'TestNewName'
  renaming back provider VDC to 'TestVCD.Test_ProviderVdcCRUD'
  adding resource pool 'resource-pool-for-vcd-02' to provider VDC
  removing resource pool 'resource-pool-for-vcd-02' from provider VDC
  adding storage profile 'Development2' to provider VDC
  removing storage profile 'Development2' from provider VDC
  disabling provider VDC 'TestVCD.Test_ProviderVdcCRUD'
  removing provider VDC 'TestVCD.Test_ProviderVdcCRUD'
*** ProviderVDC with automatic network pool
  creating provider VDC 'TestVCD.Test_ProviderVdcCRUD' using resource pool 'resource-pool-for-vcd-01' and storage profile '*'
  renaming provider VDC to 'TestNewName'
  renaming back provider VDC to 'TestVCD.Test_ProviderVdcCRUD'
  adding resource pool 'resource-pool-for-vcd-02' to provider VDC
  removing resource pool 'resource-pool-for-vcd-02' from provider VDC
  adding storage profile 'Development2' to provider VDC
  removing storage profile 'Development2' from provider VDC
  disabling provider VDC 'TestVCD.Test_ProviderVdcCRUD'
  removing provider VDC 'TestVCD.Test_ProviderVdcCRUD'
PASS: provider_vdc_test.go:186: TestVCD.Test_ProviderVdcCRUD	153.484s

Note: you need to have at least one free resource pool to test provider VDC creation, and at least two of them to test update.

[lvirbalas]

What a beefy PR, thanks! Just a couple inline comments.

[Didainius]

First pass - mainly with a few questions around ExecuteJsonRequest

[Didainius]

I think I am good in general, but body.Close() needs to be reviewed after calling executeJsonRequest

[adambarreiro]

Amazing work, very clean. Just a few doubts.

[adezxc]

Approved, just some general questions/comments