Ensure complexity, minlength and ispwned are checked on password setting (#18005) (#18015)

Backport #18005

It appears that there are several places that password length, complexity and ispwned
are not currently been checked when changing passwords. This PR adds these.

Fix #17977

Signed-off-by: Andrew Thornton <art27@cantab.net>

cmd/admin.go

@@ -335,6 +335,10 @@ func runChangePassword(c *cli.Context) error {
 	if err := initDB(); err != nil {
 		return err
 	}
+	if len(c.String("password")) < setting.MinPasswordLength {
+		return fmt.Errorf("Password is not long enough. Needs to be at least %d", setting.MinPasswordLength)
+	}
+
 	if !pwd.IsComplexEnough(c.String("password")) {
 		return errors.New("Password does not meet complexity requirements")
 	}