Add support for boot delay

[ctorkington-craven]

Description

Existing configuration_parameters allows config options defined in VirtualMachineConfigSpec.
bootOptions is a property of this defined in VirtualMachineBootOptions which includes properties such as;
bootDelay
bootOrder
efiSecureBootEnabled
enterBIOSSetup

I can see this was raised previously but with not apparenet resolution:-
#228 and #11964

Can you create an option for 'bootDelay' in the same way you created one for bootOrder(Packer option is 'boot_order').

A written overview of the feature.

The option allows the VM sheel to halt at the POST screen for a period of time to allow human interaction to press F2 to enter SETUP.

Default of 0milliseconds can be too quick for users on slower remote console connections.

Any relevant use-cases that you see.

Packer generated templates and VMs take the default value of bootDelay=0milliseconds as there is no means to alter this without additional PowerCLI.

Users request bootDelay increase to enable the 'Press F2 to enter Setup' option to allow for VM BIOS alteration to boot order (and other BIOS options).

Potential configuration

boot_delay = 5000

The equivalent PowerCLI script is:

$VM=get-vm testVM

$vmConfigSpec = New-Object VMware.Vim.VirtualMachineConfigSpec  

$vmConfigSpec.bootOptions = New-Object VMware.Vim.VirtualMachineBootOptions

&vmConfigSpec.bootOptions = 5000
	$VM.ExtensionData.ReconfigVM($vmConfigSpec)