Enable more revive linter rules (#30608)

Noteable additions:

- `redefines-builtin-id` forbid variable names that shadow go builtins
- `empty-lines` remove unnecessary empty lines that `gofumpt` does not
remove for some reason
- `superfluous-else` eliminate more superfluous `else` branches

Rules are also sorted alphabetically and I cleaned up various parts of
`.golangci.yml`.

services/user/update_test.go

@@ -94,7 +94,7 @@ func TestUpdateAuth(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 
 	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 28})
-	copy := *user
+	userCopy := *user
 
 	assert.NoError(t, UpdateAuth(db.DefaultContext, user, &UpdateAuthOptions{
 		LoginName: optional.Some("new-login"),
@@ -106,8 +106,8 @@ func TestUpdateAuth(t *testing.T) {
 		MustChangePassword: optional.Some(true),
 	}))
 	assert.True(t, user.MustChangePassword)
-	assert.NotEqual(t, copy.Passwd, user.Passwd)
-	assert.NotEqual(t, copy.Salt, user.Salt)
+	assert.NotEqual(t, userCopy.Passwd, user.Passwd)
+	assert.NotEqual(t, userCopy.Salt, user.Salt)
 
 	assert.NoError(t, UpdateAuth(db.DefaultContext, user, &UpdateAuthOptions{
 		ProhibitLogin: optional.Some(true),