api: add serial console API calls v2

Adds a new REST APIv2 to call service serial console

Co-Authored-By: Ian Wells <iawells@cisco.com>
Co-Authored-By: Sushma Korati <sushma_korati@persistent.co.in>
Co-Authored-By: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@redhat.com>

Patial-Implements: blueprint serial-ports
Change-Id: I35d94c1924caa9cbc0fcdd9c637d28e95ff31ab2
Merge "api: add serial console API calls v2"