Sync the defaults of VPNaaS forms with the server-side defaults

Also clears the unnecessary default values of remote peer subnet,
remote peer address, peer id and PSK.

Split IPSec Site connection creation form into two tabs (required
and optional parameters) since it has many parameters.

Closes-Bug: #1222255

Camel-case resource names (e.g., VPNService, IPSecPolicy...) are
replated by names with spaces like "VPN Service", "IPSec Policy"
and so on.

Change-Id: Ie0d77189ab3fc6d0722ece28abced9192ea0740b
Improves VPNaaS detail page templates

* Change "Tenant ID" to "Project ID"
* Move "Name" and "Description" to the top of the detail pages
* Show "None" if "name" or "description" is empty
* Remove colons from item names in the detail pages
* Remove "VPN type" from VPN service detail
* Arrange the order of items with the same as the creation form
* Print peer_cidrs with for loop

Closes-Bug: #1222260

Change-Id: I2293eb4b87179862c52c1c0bd7852a555955e1c0
Show IPSec Site Connection in VPN service detail

IPSec Site connections associated with VPN service are useful information.
Previously the field "VPN Connections" exist but the associated connections
are not displayed.

Closes-Bug: #1222256

Change-Id: I81da5cc6b63463102c3270fead8921bf8c10d11a
Create links between VPN resources

This commit creates cross links between VPN resource
and resolves VPN related resource UUID to its name.
This helps users to track VPN resources.

Closes-Bug: #1222264

This commit also improves an error handling when an error occurs
during retrieving a resource detail via API call.
While previously a detail page without item values is displayed,
now the index page is displayed for such case.

Change-Id: I53e03bf01ad0f359b889115068b1548c9a61ae8d
Merge "Sync the defaults of VPNaaS forms with the server-side defaults"
Merge "Improves VPNaaS detail page templates"
Merge "Show IPSec Site Connection in VPN service detail"
Merge "Create links between VPN resources"