* change(router): use `radixtree_sni` as default SSL router.
* change(route): use `radixtree_uri` as default HTTP(S) router.
* luarocks: removed `lua-resty-libr3` component by default.
* feature(router): implemented new SNI router `radixtree_sni`, and change
default router to `radixtree_uri` and `radixtree_sni`.
* optimize: avoided one lrucache call.