Reimplementation of the captchaWe drop the previous awkward implementations that would either not scale or require external dependencies. Instead, we adopt the approach in use at https://fossil-scm.org/, where a random string is converted to an ASCII art.The ASCII art itself comes from the Fossil source code.
Added the message catalog and the fonts to this package to keep things separated.TODO: The message key "Please_enter_the_captcha" is not used on upstream code and could be deleted.maybe, something from the downstram captcha code was not provide upstream.
Factored out captcha package from acs-templating, since it introduces too many external dependenciesFurthermore, as it is, this does not work under macOS (and probably not on *BSD, or windows)and breaks regression test.