Drop SSPI auth support and more Windows files (#7148)

## Dropping SSPI auth support

SSPI authentication relied on Microsoft Windows support, removal started in https://codeberg.org/forgejo/forgejo/pulls/5353, because it was broken anyway. We have no knowledge of any users using SSPI authentication. However, if you somehow managed to run Forgejo on Windows, or want to upgrade from a Gitea version which does, please ensure that you do not use SSPI as an authentication mechanism for user accounts. Feel free to reach out if you need assistance.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7148
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
Co-authored-by: Otto Richter <otto@codeberg.org>
Co-committed-by: Otto Richter <otto@codeberg.org>

modules/setting/path.go

@@ -34,11 +34,7 @@ var (
 func getAppPath() (string, error) {
 	var appPath string
 	var err error
-	if IsWindows && filepath.IsAbs(os.Args[0]) {
-		appPath = filepath.Clean(os.Args[0])
-	} else {
-		appPath, err = exec.LookPath(os.Args[0])
-	}
+	appPath, err = exec.LookPath(os.Args[0])
 	if err != nil {
 		if !errors.Is(err, exec.ErrDot) {
 			return "", err

modules/setting/setting.go

@@ -8,7 +8,6 @@ package setting
 import (
 	"fmt"
 	"os"
-	"runtime"
 	"strings"
 	"time"
 
@@ -34,7 +33,6 @@ var (
 	RunMode     string
 	RunUser     string
 	IsProd      bool
-	IsWindows   bool
 
 	// IsInTesting indicates whether the testing is running. A lot of unreliable code causes a lot of nonsense error logs during testing
 	// TODO: this is only a temporary solution, we should make the test code more reliable
@@ -42,22 +40,18 @@ var (
 )
 
 func init() {
-	IsWindows = runtime.GOOS == "windows"
 	if AppVer == "" {
 		AppVer = "dev"
 	}
 
-	// We can rely on log.CanColorStdout being set properly because modules/log/console_windows.go comes before modules/setting/setting.go lexicographically
 	// By default set this logger at Info - we'll change it later, but we need to start with something.
 	log.SetConsoleLogger(log.DEFAULT, "console", log.INFO)
 }
 
 // IsRunUserMatchCurrentUser returns false if configured run user does not match
 // actual user that runs the app. The first return value is the actual user name.
-// This check is ignored under Windows since SSH remote login is not the main
-// method to login on Windows.
 func IsRunUserMatchCurrentUser(runUser string) (string, bool) {
-	if IsWindows || SSH.StartBuiltinServer {
+	if SSH.StartBuiltinServer {
 		return "", true
 	}