Restrict supported tarball formats to actual Tarballs

The documentation is clear about the supported formats (with at least
`builtins.fetchTarball`). The way the code was written previously it
supported all the formats that libarchive supported. That is a
surprisingly large amount of formats that are likely not on the radar
of the Nix developers and users. Before people end up relying on
this (or if they do) it is better to break it now before it becomes a
widespread "feature".

Zip file support has been retained as (at least to my knowledge)
historically that has been used to fetch nixpkgs in some shell
expressions *many* years back.

Fixes #10917

src/libutil/tarfile.cc

@@ -79,7 +79,8 @@ TarArchive::TarArchive(Source & source, bool raw, std::optional<std::string> com
     }
 
     if (!raw) {
-        archive_read_support_format_all(archive);
+        archive_read_support_format_tar(archive);
+        archive_read_support_format_zip(archive);
     } else {
         archive_read_support_format_raw(archive);
         archive_read_support_format_empty(archive);
@@ -96,7 +97,8 @@ TarArchive::TarArchive(const Path & path)
     , buffer(defaultBufferSize)
 {
     archive_read_support_filter_all(archive);
-    archive_read_support_format_all(archive);
+    archive_read_support_format_tar(archive);
+    archive_read_support_format_zip(archive);
     archive_read_set_option(archive, NULL, "mac-ext", NULL);
     check(archive_read_open_filename(archive, path.c_str(), 16384), "failed to open archive: %s");
 }