hyper-boring: update to hyper 1.0.0

[howardjohn]

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This PR upgrades hyper-boring to support hyper 1.0.0-rc.3. Most of this is by moving dependencies from hyper core to hyper-util, as much of the functionality we depend on has been removed from the core.

Copied from https://github.com/cloudflare/boring/pull/107 since I made an unrepairable mistake on the first PR

[inikulin]

@howardjohn thank you for the contribution.

We would like to have hyper 1.0 under a feature flag, so we can avoid making a breaking change and to keep supporting users that use older version.

Here's a feature setup that we'd like to use: https://github.com/cloudflare/boring/compare/master...hyper1

May I ask you to put hyper 1.0 stuff under hyper1 feature flag and hyper 0.x API under hyper feature (which will be enabled by default). Please, let me know if you don't have cycles for that. We will update your PR ourselves then.

[howardjohn]

@inikulin we have moved off using hyper-boring so its not a high priority for me; if anyone is interested feel free to take over this PR/make a new one based on this. If I have some free time I may be able to pick it up, but don't want to block everyone on that.