rewrite bin/tar-entry.sh

We rewrote the `bin/tar-entry.sh` algorithm so that we do NOT have
to require Linux to produce a compressed tarball that is byte-for-byte
identical to a macOS compressed tarball for the same entry.

Changed `bin/tar-entry.sh` VERSION from "1.2 2024-03-22"
to "1.3 2024-03-25".

Added `bin/untar-entry.sh` to untar an entry from the
compressed tarball.

Added `make untar_entry_tarball` to untar all entry files.

Added `make untar_year_tarball` and `make untar_all_tarball`
stub Makefile rules.  The core it referred to does not yet exist.

Updated IOCCC manifest.  Updated `.entry.json` for `2004/sds`.

Performed `make www` to update web pages.  In most cases the
entry `index.html` added an inventory link for the new `.tar.tstamp` file.

Performed `form_entry_tarball` to complete the test of the above.

TODO: Test the results under Linux.

TODO: Update `bin/tar-year.sh`.  Update year level compressed tarballs.

TODO: Update `bin/tar-all.sh`.  Update top level compressed tarball.

TODO: Write `bin/untar-year.sh` and `bin/untar-all.sh`.

bin/README.md

@@ -367,6 +367,23 @@ bin/all-years.sh -v 3 bin/tar-year.sh -v 1 -W
 ```
 
 
+## [untar-entry.sh](untar-entry.sh)
+
+Untar an entry's a compressed tarball.
+
+Usage:
+
+```sh
+bin/untar-entry.sh -v 1 YYYY/dir
+```
+
+Suggested usage:
+
+```sh
+bin/all-run.sh -v 3 bin/untar-entry.sh -v 1
+```
+
+
 # <a name="how"></a>How IOCCC HTML content is built
 
 The [md2html.sh](md2html.sh) tool is the primary tool that