Unfortunately, we can't completely remove the ctx from git.Repository,
because the CatFileBatch still heavily depends on a parent context.
If we remove the Repository ctx, the CatFileBatch will become a mess and
create a lot of unnecessary git processes.
http://localhost:3000/-/admin/monitor/perftrace
* Before: open a repo home, dozens of git processes (duplicate cat-file)
* After: only a few (no duplicate cat-file)
before: gitrepo vs git packages
after: git package fully handle all git operations
by the way, use `WithRepo(repo)` instead of `WithDir(repo.Path)` to hide
path details.
benefits:
1. remove all unnecessary wrappers, developers no need to struggle with
"which package should be used"
2. simplify code, RepositoryFacade can (will) be used everywhere, all
"path" details are (will be) hidden
wxiaoguang