Move Result to top of core crate

[rylev]

This rather large PR is quite simple. It adds a pub use declaration to azure_core so that users can access the Result type alias from the root of azure_core like so: azure_core::Result. This is quite a common pattern in the Rust world.

The rest of the changes are simply moving all uses of azure_core's Result type to use this path so that we have consistency across the code base.

[bmc-msft]

I was hoping to ask about doing the same.

[bmc-msft]

This LGTM, the only thing I would have done differently is doing use azure_core::Result and then using Result, rather than repeatedly using azure_core::Result.

[cataggar]

Why just Result and not errror::*?

[rylev]

We could do that though I think I'd leave that for a future PR.

[rylev]

This LGTM, the only thing I would have done differently is doing use azure_core::Result and then using Result, rather than repeatedly using azure_core::Result.

I purposefully went this route since this tends to be more idiomatic. Generally speaking, unqualified Result is reserved for std::result::Result while qualified Result is used for others. This is why in the std lib docs, you often see std::io::Result used as io::Result instead of just as Result.

This isn't a hard and fast rule though obviously.