[mod2-01] adapted layout to new theme, fixed typos, only major things:
[mod2-01] adapted layout to new theme, fixed typos, only major things:

* Remove criticism of Cisco definitions (out of place, wasted space)
* "switches to the end-user" doesn't really makes sense
* Backbone as a synonim for Core Layer
* Added Backplane definition as a switch characteristic
* Remove preamble byte count from S&F definition
* Little Better explanation and wording of Microsegmentation

hlcs/advanced-networking,hlcs/advanced-networking