Update GettingStarted.md
Update GettingStarted.md

Clarified intro and powerstrip positioning; added CALICO_IP=auto and CALICO_PROFILE= example.

Former-commit-id: d2020fa89c374704f4b006c27b9d50e793395a06
robbrockbank/libcalico,alexhersh/libcalico,L-MA/libcalico,projectcalico/libnetwork-plugin,caseydavenport/libcalico,tomdee/libcalico,Symmetric/libcalico,projectcalico/libcalico,djosborne/libcalico,tomdee/libnetwork-plugin,TrimBiggs/libnetwork-plugin,insequent/libcalico,plwhite/libcalico,TrimBiggs/libcalico,TrimBiggs/libnetwork-plugin