Documentation update and bug fix on P4 test
# Reporters
- Georgios P. Katsikas (UBITECH)
# Description
The P4 test uses an external Rust program acting as a latency probe.
This program creates KPI descriptors on the Monitoring subsystem.
Recently, such KPI descriptors require one additional field to create, thus the compilation process of the latency probe was failing.
Also, better documentation is needed on how to compile the latency probe.
## Deployment environment
- Linux Ubuntu server 22.04
- MicroK8s
- TeraFlowSDN develop
## TFS deployment settings
- context device service webui
- no particular configuration
## Sequence of actions that resulted in the bug
- `cargo build` command fails to compile the Rust program
## Expected behaviour
- `cargo build` must succeed and 2 executables (tfsagent, tfsping) must be generated as a result
issue