Refactor to use urfave/cli/v2 (#25959)

Replace #10912

And there are many new tests to cover the CLI behavior

There were some concerns about the "option order in hook scripts"
(https://github.com/go-gitea/gitea/pull/10912#issuecomment-1137543314),
it's not a problem now. Because the hook script uses `/gitea hook
--config=/app.ini pre-receive` format. The "config" is a global option,
it can appear anywhere.

----

## ⚠️ BREAKING ⚠️

This PR does it best to avoid breaking anything. The major changes are:

* `gitea` itself won't accept web's options: `--install-port` / `--pid`
/ `--port` / `--quiet` / `--verbose` .... They are `web` sub-command's
options.
    * Use `./gitea web --pid ....` instead
* `./gitea` can still run the `web` sub-command as shorthand, with
default options
* The sub-command's options must follow the sub-command
* Before: `./gitea --sub-opt subcmd` might equal to `./gitea subcmd
--sub-opt` (well, might not ...)
    * After: only `./gitea subcmd --sub-opt` could be used
    * The global options like `--config` are not affected

contrib/environment-to-ini/environment-to-ini.go

@@ -9,7 +9,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 
-	"github.com/urfave/cli"
+	"github.com/urfave/cli/v2"
 )
 
 func main() {
@@ -46,22 +46,22 @@ func main() {
 	and "GITEA__LOG_0x2E_CONSOLE__STDERR=false". Other examples can be found
 	on the configuration cheat sheet.`
 	app.Flags = []cli.Flag{
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "custom-path, C",
 			Value: setting.CustomPath,
 			Usage: "Custom path file path",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "config, c",
 			Value: setting.CustomConf,
 			Usage: "Custom configuration file path",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "work-path, w",
 			Value: setting.AppWorkPath,
 			Usage: "Set the gitea working path",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "out, o",
 			Value: "",
 			Usage: "Destination file to write to",