internetarchive: fix server side copy files with &

Before this change, server side copy of files with & gave the error:

    Invalid Argument</Message><Resource>x-(amz|archive)-copy-source
    header has bad character

This fix switches to using url.QueryEscape which escapes everything
from url.PathEscape which doesn't escape &.

Fixes #8754

backend/internetarchive/internetarchive.go

@@ -1339,7 +1339,7 @@ func quotePath(s string) string {
 	seg := strings.Split(s, "/")
 	newValues := []string{}
 	for _, v := range seg {
-		newValues = append(newValues, url.PathEscape(v))
+		newValues = append(newValues, url.QueryEscape(v))
 	}
 	return strings.Join(newValues, "/")
 }