Support for custom resource build suffix

[antoni0shuleshov]

Description

Add an optional parameter custom_resource_build_suffix, that is similar to custom_resource_build_prefix. If this parameter is set the temporary resources will be named accordingly. E.g. Azure KeyVault resource will be named custom_resource_build_prefixresourcetypecustom_resource_build_suffix
If custom_resource_build_suffix is not set the name will be custom_resource_build_prefix + resourcetype + 5 character random alphanumeric string

Use Case(s)

In case of using Azure Policy that enforces special naming convention packer script will fail.