Relax validation on handler_type

MSP-9228

Inclusion validation was incorrect as it does not properly handle
aliasing in metasploit-framework, so restore the presence validation.
Template.write!

MSP-9228

Add an exception raising version of Template.write so that specs will
fail fast.
handler_type sequence for aliases

MSP-9228

:metasploit_model_module_ancestor_handler_type is independent of
:metasploit_module_module_handler_type and is meant for
Metasploit::Model::Module::Ancestor#handler_type to mimic the handler
aliasing in metasploit-framework.
Use handler_type alias in templates

MSP-9228