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

cmd/web.go

@@ -23,14 +23,14 @@ import (
 	"code.gitea.io/gitea/routers/install"
 
 	"github.com/felixge/fgprof"
-	"github.com/urfave/cli"
+	"github.com/urfave/cli/v2"
 )
 
 // PIDFile could be set from build tag
 var PIDFile = "/run/gitea.pid"
 
 // CmdWeb represents the available web sub-command.
-var CmdWeb = cli.Command{
+var CmdWeb = &cli.Command{
 	Name:  "web",
 	Usage: "Start Gitea web server",
 	Description: `Gitea web server is the only thing you need to run,
@@ -38,26 +38,29 @@ and it takes care of all the other things for you`,
 	Before: PrepareConsoleLoggerLevel(log.INFO),
 	Action: runWeb,
 	Flags: []cli.Flag{
-		cli.StringFlag{
-			Name:  "port, p",
-			Value: "3000",
-			Usage: "Temporary port number to prevent conflict",
+		&cli.StringFlag{
+			Name:    "port",
+			Aliases: []string{"p"},
+			Value:   "3000",
+			Usage:   "Temporary port number to prevent conflict",
 		},
-		cli.StringFlag{
+		&cli.StringFlag{
 			Name:  "install-port",
 			Value: "3000",
 			Usage: "Temporary port number to run the install page on to prevent conflict",
 		},
-		cli.StringFlag{
-			Name:  "pid, P",
-			Value: PIDFile,
-			Usage: "Custom pid file path",
+		&cli.StringFlag{
+			Name:    "pid",
+			Aliases: []string{"P"},
+			Value:   PIDFile,
+			Usage:   "Custom pid file path",
 		},
-		cli.BoolFlag{
-			Name:  "quiet, q",
-			Usage: "Only display Fatal logging errors until logging is set-up",
+		&cli.BoolFlag{
+			Name:    "quiet",
+			Aliases: []string{"q"},
+			Usage:   "Only display Fatal logging errors until logging is set-up",
 		},
-		cli.BoolFlag{
+		&cli.BoolFlag{
 			Name:  "verbose",
 			Usage: "Set initial logging to TRACE level until logging is properly set-up",
 		},