Refactor `git.Command.Run*`, introduce `RunWithContextString` and `RunWithContextBytes` (#19266)

This follows 
* https://github.com/go-gitea/gitea/issues/18553

Introduce `RunWithContextString` and `RunWithContextBytes` to help the refactoring. Add related unit tests. They keep the same behavior to save stderr into err.Error() as `RunInXxx` before.

Remove `RunInDirTimeoutPipeline` `RunInDirTimeoutFullPipeline` `RunInDirTimeout` `RunInDirTimeoutEnv`  `RunInDirPipeline`  `RunInDirFullPipeline`  `RunTimeout`, `RunInDirTimeoutEnvPipeline`, `RunInDirTimeoutEnvFullPipeline`, `RunInDirTimeoutEnvFullPipelineFunc`.

Then remaining `RunInDir` `RunInDirBytes` `RunInDirWithEnv` can be easily refactored in next PR with a simple search & replace:
* before: `stdout, err := RunInDir(path)`
* next: `stdout, _, err := RunWithContextString(&git.RunContext{Dir:path})`

Other changes:
1. When `timeout <= 0`, use default. Because `timeout==0` is meaningless and could cause bugs. And now many functions becomes more simple, eg: `GitGcRepos` 9 lines to 1 line. `Fsck` 6 lines to 1 line.
2. Only set defaultCommandExecutionTimeout when the option `setting.Git.Timeout.Default > 0`

1 files changed, 5 insertions, 1 deletions

diff --git a/modules/process/manager.go b/modules/process/manager.go
index 50dbbbe6c8..26dd6d535f 100644
--- a/modules/process/manager.go
+++ b/modules/process/manager.go
@@ -86,6 +86,10 @@ func (pm *Manager) AddContext(parent context.Context, description string) (ctx c
 // Most processes will not need to use the cancel function but there will be cases whereby you want to cancel the process but not immediately remove it from the
 // process table.
 func (pm *Manager) AddContextTimeout(parent context.Context, timeout time.Duration, description string) (ctx context.Context, cancel context.CancelFunc, finshed FinishedFunc) {
+	if timeout <= 0 {
+		// it's meaningless to use timeout <= 0, and it must be a bug! so we must panic here to tell developers to make the timeout correct
+		panic("the timeout must be greater than zero, otherwise the context will be cancelled immediately")
+	}
 	ctx, cancel = context.WithTimeout(parent, timeout)
 
 	ctx, pid, finshed := pm.Add(ctx, description, cancel)
@@ -239,7 +243,7 @@ func (pm *Manager) ExecDirEnv(ctx context.Context, timeout time.Duration, dir, d
 // Returns its complete stdout and stderr
 // outputs and an error, if any (including timeout)
 func (pm *Manager) ExecDirEnvStdIn(ctx context.Context, timeout time.Duration, dir, desc string, env []string, stdIn io.Reader, cmdName string, args ...string) (string, string, error) {
-	if timeout == -1 {
+	if timeout <= 0 {
 		timeout = 60 * time.Second
 	}