`resource.execute()` should accept steps directly (unwrapped)

[benjie]

We originally required {step: Step, codec?: PgCodec} because we needed to encode the parameters. But we know the types of the arguments, so we should be able to accept steps directly too and just use the default codec for that parameter if one isn't specified.

[jsmnbom]

I'm using this helper in my own code. It seems to work just fine, maybe it is helpful to others or to a proper implementation.
Not gonna make a PR due to a few reasons:

• I am unsure if it handles Step typing correctly (like, how Step and ObjectStep interacts and such - really just not sure myself - all i can say is that it works, and seems to add a fair bit of convenience).
• Unsure if execute should also accept typed arrays.
• PgResourceParameter doesn't have a typed required parameter meaning it isn't possible to figure out which fields in the args should be optional and not - and I am unsure if adding a TRequired extends boolean to it would be a breaking change and such, so felt better leaving it up to Benjie :)

type GetCodecValue<T>
  = T extends PgCodec<any, any, any, infer TFromJavaScript, any, any, any>
    ? TFromJavaScript
    : never

export type PgResourceParameterObject<TParameters extends readonly PgResourceParameter[] | undefined>
  = TParameters extends readonly PgResourceParameter[]
    ? { [P in TParameters[number] as P['name'] extends string ? P['name'] : never]?: Step<GetCodecValue<P['codec']>>; }
    : never

function resourceExecute<TResource extends PgResource>(
  resource: TResource,
  args: PgResourceParameterObject<TResource['parameters']>,
  mode?: PgSelectMode,
): Step<unknown> {
  return resource.execute((resource.parameters ?? []).map(parameter => ({
    name: parameter.name ?? undefined,
    codec: parameter.codec,
    step: (args as any)[parameter.name!],
  })), mode)
}