Support WASI KV

[radu-matei]

I would really like to use the increment function.

With spinframework/spin#2895, Spin already supports it.

[karthik2804]

We already support it, it is just that we do not provide an extra layer of bindings like we do for Spin API. We can currently use it like import { store } from "wasi:keyvalue@0.2.0-draft2". If we want to maintain a separate layer of bindings, it would possibly make sense to have a wasi-cloud-core package that can be used.

[karthik2804]

The previous statement is not entirely true because we started including the interface only in spin3-http, the default template only uses spin-http while building so that needs to be edited.

[karthik2804]

@radu-matei are we okay to close this as it will not be part of the spin-sdk?