Add bundle download for repository

[jolheiser]

This PR adds another download type for repositories, bundle.

This currently always bundles using --all, since I'd imagine it's almost always more useful to have the entire repo history.

In the future, bundling could be considered for backups since they are standalone repositories, more or less.

One thing that I couldn't seem to shake when writing this, it seems like the bundle file refused to copy correctly unless I closed the file after creation (and subsequently re-opened to allow the io.Copy).
Please let me know if I missed something silly. 🙂

[lunny]

Please resolve the conflicts.

[jolheiser]

This should be ready to test again.

1. Sorry for the unrelated changes, I'm not sure whether GoLand or gofmt is responsible for the build tags (my guess is the former), but they have been duplicated because the old style has been deprecated in favor of //go:build
2. Due to bundles needing to be written to a file (rather than to stdout), I had to re-add code to temporarily store them until they could be piped out to the caller.

[lunny]

Since .zip and .tar.gz will only include current branch codes, it's confusing that this will bundle --all. Maybe add two menu items, one is for current branch another is --all.

[jolheiser]

Alright, this now downloads a bundle at the current branch/commit.

After merging, I will follow up with a PR that adds the --all bundle to repo settings, as it's more of a complete backup option.

[codecov-commenter]

Codecov Report

Merging #14538 (6800427) into main (1cd4a3b) will decrease coverage by 0.00%.
The diff coverage is 17.50%.

@@            Coverage Diff             @@
##             main   #14538      +/-   ##
==========================================
- Coverage   45.50%   45.49%   -0.01%     
==========================================
  Files         762      762              
  Lines       85940    85973      +33     
==========================================
+ Hits        39108    39117       +9     
- Misses      40521    40546      +25     
+ Partials     6311     6310       -1     

Impacted Files	Coverage Δ
cmd/embedded_stub.go	0.00% <ø> (ø)
modules/auth/pam/pam_stub.go	0.00% <ø> (ø)
modules/git/blob_nogogit.go	61.19% <ø> (ø)
modules/git/commit_info_nogogit.go	60.60% <ø> (ø)
modules/git/last_commit_cache_nogogit.go	35.84% <ø> (ø)
modules/git/notes_nogogit.go	71.42% <ø> (ø)
modules/git/parse_nogogit.go	56.32% <ø> (ø)
modules/git/pipeline/lfs_nogogit.go	0.00% <ø> (ø)
modules/git/repo.go	43.31% <0.00%> (-4.40%)	⬇️
modules/git/repo_archive.go	0.00% <0.00%> (ø)
... and 29 more

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