Saves a resource to disk to the given path, using a [ResourceFormatSaver] that recognizes the resource object. If [param path] is empty, [ResourceSaver] will try to use [member Resource.resource_path].
The [param flags] bitmask can be specified to customize the save behavior using [enum SaverFlags] flags.
Returns [constant OK] on success.
+ [b]Note:[/b] When the project is running, any generated UID associated with the resource will not be saved as the required code is only executed in editor mode.