feat: support Storage Box CRUD

[jooola]

Add support for the Storage Box CRUD operations.

• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-list-storage-boxes
• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-create-a-storage-box
• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-get-a-storage-box
• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-update-a-storage-box
• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-delete-storage-box
• https://docs.hetzner.cloud/reference/hetzner#storage-boxes-list-content-of-storage-box

[codecov]

Codecov Report

❌ Patch coverage is 98.23529% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.32%. Comparing base (4395115) to head (6774fe4).
⚠️ Report is 53 commits behind head on storage-boxes.

Files with missing lines	Patch %	Lines
hcloud/storage_boxes/domain.py	97.59%	2 Missing ⚠️
hcloud/storage_boxes/client.py	98.75%	1 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                @@
##           storage-boxes     #529      +/-   ##
=================================================
+ Coverage          96.21%   96.32%   +0.10%     
=================================================
  Files                 67       70       +3     
  Lines               2983     3153     +170     
=================================================
+ Hits                2870     3037     +167     
- Misses               113      116       +3     

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[jooola]

The bound model method were not implemented, I would like to first build the base client and implement all the bound model methods at the end, once we are happy with the shape of the API.