Renames Actions\Gateways\Create -> Actions\Gateways\ProvisionGateway,
since its auto-derived AvailableActions name (from the class filename)
collided with Actions\Networks\Create - both take a Networks $network
first constructor param, so both would register as name=create,
input=Networks, making the provision-gateway action unreachable via the
generic do/{action} dispatcher.
ProvisionGateway now also:
- accepts iaas_repository_image_id in the request body, pinning the new
gateway to a specific firewall image the same way VDC creation already
can, instead of always resolving the config-driven default.
- refuses to run if the network already has a gateway, leaving a system
comment instead of risking a duplicate/conflicting IP (both old and new
firewalls' LAN NIC want the same fixed 10.128.0.1).
Together with the existing, already-cascading DELETE /iaas/gateways/{id},
this makes "delete then provision-gateway with a different image" the
supported flow for replacing a VDC's firewall.
Requires running `php artisan leo:register-actions` once per environment
to (re)create the provision-gateway AvailableActions row under its new
class name.