Added hostcalls for the new builder api hostcalls

[computermouth]

Added the new hostcalls in in a new KvStore namespace.

I asked @elliottt if it was alright to leave the component hostcalls unimplemented, and he said that'd be fine for getting these and the new SDK out the door, though it will cause the viceroy_test macro tests to fail on the component.

I think most of this is pretty straightforward, the only real weird bit is some of the handle conversions, like

impl From<types::KvStoreLookupHandle> for types::PendingKvLookupHandle {
    fn from(h: types::KvStoreLookupHandle) -> types::PendingKvLookupHandle {
        // h.into() was doing infinite recursion
        let s = unsafe { h.inner() };
        s.into()
    }
}

Not sure if there's a better way to get around this, can you turbofish the into?

[ulyssa]

This looks good to me! Thank you for adding these, these are great! 🙏

[ulyssa]

I think you may want to merge main to pull in #432 and then re-run make adapter to make sure the right .wasm file lands.