wasmtime: Add outbound HTTP capability to the shim

[Mossaka]

I am assuming that component targeting wasi-http is capable of making outbound HTTP requests already, but we don't have a test case covering that. I also think that wasi-cli component is capable of using wasi sockets to make outbound HTTP requests today but not to https. So it will be useful to add wasi-http imports to the wasi-cli components.

• add a test case for a wasi-http component to make outbound HTTP requests
• add wasi-http capability to wasi-cli components
• add a test case for wasi-cli component to make outbound HTTP requests

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Open questions

1. it might be undesriable for apps to make outbound https to any hosts but what's the best solution to add app capabilities to the shims?