Update docs for each ThunderbirdComponentResource to describe resources

[ryanjjung]

One thing this PR does is resolve Issue #75.

Another thing it does is get rid of the concept of "outputs" entirely from our component resources. "Why?" you might ask. I had initially thought it might be a good way to get at programmatically generated data like IDs and ARNs that we don't control ourselves, the way you do in Terraform, but this is not the case. These outputs are only ever printed to the CLI, and there is no way of accessing them once you push them through the register_outputs call the Pulumi docs say we should make.

As it turns out, though, outputs aren't really a thing, as the Pulumi devs attest in this thread. There they describe a convention:

CyrusNajmabadi has taken to passing the empty object to registerOutputs unconditionally because it basically doesn't mean anything.

So this PR deprecates the use of "outputs". In the future, we'll remove it, opting for the convention of always using an empty dict.