feat: Add bytes affine

[bsbds]

Based on: #656

Please briefly answer these questions:

• what problem are you trying to solve? (or if there's no problem, what's the motivation for this change?)

  Adds a new type BytesAffine, which defines the order of the keys. FYI:

• https://etcd.io/docs/v3.3/learning/api/#key-ranges

• https://github.com/etcd-io/etcd/blob/e68afe7eb7ce3e5f83deb2a8ad58faa3b35494b9/pkg/adt/interval_tree.go#L919-L947

• what changes does this pull request make?

• are there any non-obvious implications of these changes? (does it break compatibility with previous versions, etc)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 79.59184% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 75.07%. Comparing base (40763a8) to head (57bea08). Report is 10 commits behind head on master.

Files	Patch %	Lines
crates/xlineapi/src/interval.rs	79.59%	8 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #667 +/- ## ========================================== - Coverage 75.18% 75.07% -0.11% ========================================== Files 175 176 +1 Lines 26793 26852 +59 Branches 26793 26852 +59 ========================================== + Hits 20144 20160 +16 - Misses 5437 5479 +42 - Partials 1212 1213 +1 ```

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