perl implementation of crc32 algorithm added

perl_crc32.lua

@@ -0,0 +1,20 @@
+if ffi == nil then
+    if require == nil then
+        error('You must restart tarantool')
+    end
+    ffi = require('ffi')
+end
+
+ffi.cdef[[
+    unsigned perl_crc32(const char *key, unsigned len);
+]]
+
+local libperlcrc32 = ffi.load("perlcrc32")
+
+function perl_crc32(key)
+    if type(key) ~= "string" then
+        error("String key is expected in perl_crc32: '" .. key .. "'")
+    end
+
+    return libperlcrc32.perl_crc32(key, #key)
+end