support copts and linkopts per package

there must be some mechanism for configuring these options per package in the stack, at the moment this is only possible at the top-level via the bazelize plugin. it might be that this will have to remain top level with a project being a composition of several bazelize elements in order to write out different package rules. eg:https://github.com/ApolloAuto/apollo/blob/d798f5529d2001f807e6eb1fdc37cb74e3dddc36/third_party/boost.BUILD