base32: A new program similar to base64

base32: A new program similar to base64

Suggested in https://bugzilla.redhat.com/1250113

* AUTHORS: Add base32.
* THANKS.in: Add suggester.
* README: Reference the new program.
* NEWS: Mention the new program.
* src/.gitignore: Ignore the new binary.
* bootstrap.conf: Reference the gnulib base32 module.
* build-aux/gen-lists-of-programs.sh: Add base32.
* man/base32.x: A new template.
* man/.gitignore: Ignore the new man page.
* man/local.mk: Reference the new man page.
* doc/coreutils.texi (base32 invocation): Document the new command.
* src/local.mk: Adjust to build base32 based on base64.c.
* src/base64.c: Parameterize to use the correct headers,
functions and buffer sizes, depending on which binary
is being built.
* tests/misc/base64.pl: Adjust to test both base32 and base64.
* tests/misc/tty-eof.pl: Add base32 as a program that
accepts input on stdin without any options specified.
* scripts/git-hooks/commit-msg: Add base32 to the template.