This commit refactors functionality from the Router class into separate,
dedicated classes.
There are a few behavior changes that came as a result of discussion on
what the correct behavior should be.
In addition, many things Router was previously doing can now be provided
callback functions to alert the calling point when the asynchronous
action completes, successfully or otherwise.
* Import cxxopts to replace getopts usage
* Add visual studio build things
* Fixup abseil build parts
* Replace __attribute__((unused)) with ABSL_ATTRIBUTE_UNUSED
* Fixup minor windows build issues
* Replace getopts usage
* Temporarily fixup .rc files
* More minor windows fixes
* Get a working build
* Revert .rc files
* Revert changes to nodedb
