feat(el): Support txtime for sending Ethernet packets (on Linux) #963

Job	Run time
Debug Build & Unit Tests (gcc)	2m 39s
Debug Build & Unit Tests (gcc, 32bit)	3m 19s
Debug Build & Unit Tests without Subscriptions (gcc)	1m 24s
Debug Build & Unit Tests with Diagnostics (gcc)	2m 31s
Debug Build & Unit Tests with multithreading (gcc)	1m 51s
Debug Build & Unit Tests with Alarms&Conditions (gcc)	11m 33s
Debug Build & Unit Tests (clang)	4m 56s
Debug Build & Unit Tests (tcc)	2m 25s
Encryption (MbedTLS) Build & Unit Tests (gcc)	2m 6s
PubSub Encryption (MbedTLS) Build & Unit Tests (gcc)	2m 24s
PubSub SKS Build & Unit Tests (gcc)	6h 0m 14s
Encryption (OpenSSL) Build & Unit Tests (gcc)	2m 3s
Encryption (LibreSSL) Build & Unit Tests (gcc)	5m 21s
TPM Tool Build	3m 47s
Release Build	2m 0s
Amalgamation Build	54s
Amalgamation Build with Multithreading	1m 11s
Valgrind Build & Unit Tests with MbedTLS (gcc)	17m 32s
Valgrind Build & Unit Tests with OpenSSL (gcc)	15m 58s
Valgrind Examples with MbedTLS (gcc)	1h 10m 21s
Valgrind Examples with OpenSSL (gcc)	1h 15m 59s
Clang Static Analyzer	4m 3s
Build All Companion Specifications	16m 12s
	10h 10m 43s

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