toolcontext: add switches to create_toolcontext for connections and filters init

toolcontext: add switches to create_toolcontext for connections and filters init

Make it possible to decide whether we want to initialize connections and
filters together with toolcontext creation.

Add "filters" and "connections" fields to struct
cmd_context_initialized_parts and set these in cmd_context.initialized
instance accordingly.

(For now, all create_toolcontext calls do initialize connections and
filters, we'll change that in subsequent patch appropriately.)