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

1 files changed, 5 insertions, 4 deletions

diff --git a/cmd/docs.go b/cmd/docs.go
index 901d0abd1c..605d02e3ef 100644
--- a/cmd/docs.go
+++ b/cmd/docs.go
@@ -8,11 +8,11 @@ import (
 	"os"
 	"strings"
 
-	"github.com/urfave/cli"
+	"github.com/urfave/cli/v2"
 )
 
 // CmdDocs represents the available docs sub-command.
-var CmdDocs = cli.Command{
+var CmdDocs = &cli.Command{
 	Name:        "docs",
 	Usage:       "Output CLI documentation",
 	Description: "A command to output Gitea's CLI documentation, optionally to a file.",
@@ -23,8 +23,9 @@ var CmdDocs = cli.Command{
 			Usage: "Output man pages instead",
 		},
 		&cli.StringFlag{
-			Name:  "output, o",
-			Usage: "Path to output to instead of stdout (will overwrite if exists)",
+			Name:    "output",
+			Aliases: []string{"o"},
+			Usage:   "Path to output to instead of stdout (will overwrite if exists)",
 		},
 	},
 }