Use `bytes::Bytes` for `binary`

[sfackler]

Before this PR

The Conjure binary type was backed by Vec<u8>.

After this PR

==COMMIT_MSG== The Conjure binary type is now backed by bytes::Bytes. ==COMMIT_MSG==

We already use Bytes in the conjure_http interfaces, and this more generally supports some zero-copy workflows.

Closes #340

[changelog-app[bot]]

Generate changelog in changelog-dir>`changelog/@unreleased`</changelog-dir

What do the change types mean?

- `feature`: A new feature of the service. - `improvement`: An incremental improvement in the functionality or operation of the service. - `fix`: Remedies the incorrect behaviour of a component of the service in a backwards-compatible way. - `break`: Has the potential to break consumers of this service's API, inclusive of both Palantir services and external consumers of the service's API (e.g. customer-written software or integrations). - `deprecation`: Advertises the intention to remove service functionality without any change to the operation of the service itself. - `manualTask`: Requires the possibility of manual intervention (running a script, eyeballing configuration, performing database surgery, ...) at the time of upgrade for it to succeed. - `migration`: A fully automatic upgrade migration task with no engineer input required. _Note: only one type should be chosen._

How are new versions calculated?

- ❗The `break` and `manual task` changelog types will result in a major release! - 🐛 The `fix` changelog type will result in a minor release in most cases, and a patch release version for patch branches. This behaviour is configurable in autorelease. - ✨ All others will result in a minor version release.

Type

- [ ] Feature - [ ] Improvement - [ ] Fix - [x] Break - [ ] Deprecation - [ ] Manual task - [ ] Migration

Description

The Conjure `binary` type is now backed by `bytes::Bytes`. **Check the box to generate changelog(s)** - [x] Generate changelog entry