Allow for multiple secrets during resource creation

[windmill-internal-app]

/ai When creating a resource, you can set some fields to automatically become a secret variable with the same name as the resource. But it only works for 1 secret. Improve it so that if there is only one secret set during resource creation, behavior stays the same (one secret variable with the same band), but if there are many, create n secret variables with _field_name appended to each one. Request made by @diegoimbert