luarocks: Set FORCE_CONFIG=false in hardcoded config

FORCE_CONFIG=true is preventing local .rocks/config-5.1.lua from loading.
Local config is often used to populate rocks_servers with own rocks servers and with original luarocks

This patch changes FORCE_CONFIG to true in generated luarocks.core.hardcoded to allow using
project-side config-5.1.lua for luarocks configuration to avoid dirty and ugly hacks

changelogs/unreleased/luarocks-disable-force-config.md

+## luarocks
+
+ * set FORCE_CONFIG=false for luarocks config to allow loading project-side .rocks/config-5.1.lua

extra/luarocks/hardcoded.lua.cmake

@@ -6,7 +6,7 @@ LUA_INTERPRETER=[[tarantool]],
 LUA_MODULES_LIB_SUBDIR=[[/lib/tarantool]],
 LUA_MODULES_LUA_SUBDIR=[[/share/tarantool]],
 SYSCONFDIR=[[@CMAKE_INSTALL_FULL_SYSCONFDIR@/tarantool/rocks]],
-FORCE_CONFIG=true,
+FORCE_CONFIG=false,
 ROCKS_TREE=[[/usr/local/]],
 ROCKS_SUBDIR=[[/share/tarantool/rocks]],
 ROCKS_SERVERS={