improve lua interpreter autodetection

%luarocks_make modernized to handle cross-Lua builds (build module for 5.1)

add %{lua_modules_make_available_for_older_versions} (see https://www.altlinux.org/Lua_Policy)

replace %lua_version with %current_lua_version
add %luaXX_modulesdir macros
minor rpath "safety net"

Added macro %lua_version

improved %luarocks_make : make local tree more more accurate
fix %_bindir commands

add macros:

initial build for ALT Linux Sisyphus