Move `aws_smithy_http::operation::error::BuildError` into `aws-smithy-types` (#3032)

## Motivation and Context
Takes care of the first part of
https://github.com/awslabs/smithy-rs/issues/3054

 (the remaining part is
denoted as `TODO(runtimeCratesVersioningCleanup)` and until that's done
the issue will not be closed).

## Description
This PR moves from `aws-smithy-http::operation::error::{BuildError,
SerializationError}` to
`aws-smithy-types::error::operation::{BuildError, SerializationError}`.

Within the origin crate, we leave "breadcrumbs" (i.e. reexports) for
existing customers of the items above so they are not broken by the
move. The breadcrumps will be removed by the part two of the issue.

As part of the move, `aws_smithy_http::endpoint::EndpointPrefix::new`
now returns its `crate::endpoint::error::InvalidEndpointError` instead
of `crate::operation::error::BuildError` for two reasons:
- `BuildError` is now in a stable crate and for an `InvalidUri` variant
to be created, it needed to take a `http::uri::InvalidUri` from a
unstable crate, which we cannot expose in public API.
- The new error is more closely related to the endpoint business.

## Testing
Relied on the tests in CI.

## Checklist
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates

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choice._

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Co-authored-by: John DiSanti <jdisanti@amazon.com>