Add an http outcalls example

[mihailjianu1]

This showcases two ways of using the http outcalls feature in rust, and adds them to the icp ninja examples:

• A replicated http outcall to a constant, fairly deterministic service
• a non replicated outcall to a volatile service

In the case of the replicated http outcall, we also showcase the use of transform queries and how / why they help reach consensus.

[fxgst]

Is this supposed to replace the HTTP Get and HTTP Post examples? They seem quite overlapping

[letmejustputthishere]

i think there are some CI workflows missing https://github.com/dfinity/examples/blob/master/ADDING_AN_EXAMPLE.md#ci

https://github.com/dfinity/examples/blob/master/NINJA_CONTRIBUTING.md#preparing-the-pr