[SDFAB-1178] Allows to read ingress and egress counters separately

[daniele-moro]

Depends on:

• https://github.com/stratum/fabric-tna/pull/520
• https://gerrit.onosproject.org/c/onos/+/25447

This PR consider only the read path. Code is taken partially from:

• https://github.com/omec-project/up4/pull/282
• https://github.com/omec-project/up4/pull/279

[pierventre]

there are ci failures - is that expected ?