replace portmapping FNV1-128 by FNV1-64 + Base64

replace portmapping FNV1-128 by FNV1-64 + Base64

FNV1 128bit hash produces 16 bytes results but they cannot easily be
represented as a UTF-8 readable string of 16 characters as required
by SAPI/DAPI OpenROADM specification.
Base64 conversion allows to fix this but generates an overhead.
By using FNV1 64bit hash + Base64, we can guarantee the results
will not exceed 16 characters (usually around 13).

Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: I559b5439f83cffc619a1db4e29b9d78c8401ed06