Make Requests Processes and create process hierarchy. Associate OpenRepository with context. (#17125)

This PR registers requests with the process manager and manages hierarchy within the processes.

Git repos are then associated with a context, (usually the request's context) - with sub commands using this context as their base context.

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/git/repo_commit_gogit.go

@@ -40,7 +40,7 @@ func (repo *Repository) ConvertToSHA1(commitID string) (SHA1, error) {
 		}
 	}
 
-	actualCommitID, err := NewCommand("rev-parse", "--verify", commitID).RunInDir(repo.Path)
+	actualCommitID, err := NewCommandContext(repo.Ctx, "rev-parse", "--verify", commitID).RunInDir(repo.Path)
 	if err != nil {
 		if strings.Contains(err.Error(), "unknown revision or path") ||
 			strings.Contains(err.Error(), "fatal: Needed a single revision") {