Avoid implicit defaults for environment #43
Description
Currently, the environment is set to "dev" by default, but given that the user is meant to specify the environment with the the sqlmes_asset decorator, maybe it would make sense to save it on the config. Otherwise, when creating assets, the environment from the decorator is used, but given no parameter is passed to the SQLMeshResource, it defaults to "dev", which is not very intuitive.
IMO, the best would be to have it specified on the config, and if the user wants to use a different one to deploy in a different environment, it should be documented that it can also be passed to the run method from SQLMeshResource.