* Change port index in port_config.ini to 1-based
* Add default port index to port_config.ini, change platform plugins to accept 1-based port index
* fix port index in sfp_event.py
sai_xml contains info about port splits, previously it simply linked to the MSN3800 sai xml, which does not have splits. New version describes splits and speeds according to Mellanox-SN3800-D112-C8 SKU.
Practically it can cause port recreation on SAI init.
Signed-off-by: Mykola Faryma <mykolaf@mellanox.com>