Configurations for long-strip stave

Add chip and star emulator example configurations for a long-strip stave. Not exactly sure if they should be put in the repository, but they might be useful for probing issues similar to #92 (closed) involving multiple front-end links.

Also add an option in the connectivity config to specify chip IDs via a field "id". Currently the chip IDs for FrontEndCfg are set from register configuration file via "config" for each chip. For testing/debugging multiple FEs, it might be convenient to use the same register config file (e.g. configs/defaults/default_star.json) for all chips but only change chip IDs. If the "id" field is provided, its value overwrites the chip ID from the register config file.