Add support for sha256 repositories (#23894)

Currently only SHA1 repositories are supported by Gitea. This adds
support for alternate SHA256 with the additional aim of easier support
for additional hash types in the future.

Fixes: #13794
Limited by: https://github.com/go-git/go-git/issues/899
Depend on: #28138

<img width="776" alt="图片" src="5448c9a7-608e-4341-a149-5dd0069c9447">

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Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

options/locale/locale_en-US.ini

@@ -970,6 +970,8 @@ issue_labels_helper = Select an issue label set.
 license = License
 license_helper = Select a license file.
 license_helper_desc = A license governs what others can and can't do with your code. Not sure which one is right for your project? See <a target="_blank" rel="noopener noreferrer" href="%s">Choose a license.</a>
+object_format = Object Format
+object_format_helper = Object format of the repository. Cannot be changed later. SHA1 is most compatible.
 readme = README
 readme_helper = Select a README file template.
 readme_helper_desc = This is the place where you can write a complete description for your project.
@@ -1038,6 +1040,7 @@ desc.public = Public
 desc.template = Template
 desc.internal = Internal
 desc.archived = Archived
+desc.sha256 = SHA256
 
 template.items = Template Items
 template.git_content = Git Content (Default Branch)