[arch-general] Remove Clisp from repository

[Gilgamesh]

Hello, firstly, I don't know where I can send this message, so sorry if
this is the wrong place.

Clisp (an ANSI Common Lisp interpreter) hadn't received a new release
since 2010-07-07 and the last update on the extra repo was on
2019-01-11, so I thought as we have others better options than Clisp,
like sbcl on the extra repo, that has an active development, may be
better if the Clisp package is removed from the arch repositories.