Documentation on packaging and publishing WIT packages

[brooksmtownsend]

In our documentation we have information about how to build and publish Wasm components, and with the introduction of wkg I think we should add information about how to build and publish WIT packages (as Wasm).

Additionally, I think we can offer some guidance here as well, e.g. if you're publishing a component other folks are going to compose with over the interface wasmcloud:blobby/foobar, the interface goes to ghcr.io/wasmcloud/wasmcloud/blobby:0.2.0 and the component goes to ghcr.io/wasmcloud/blobby:0.2.0?

cc @thomastaylor312