Improve log entries with context, more accurate string error, and more information

[AltraMayor]

Add context to log entries with "%s(%s): ". The first string is __func__, and the second string is some proper context. A common example of context is iface->name to identify the interface associated with the log entry.

Review all calls of strerror() and replace the ones that are dealing with DPDK's errors with rte_strerror().

Add "(errno=%i): %s\n" to G_LOG()'s that have errno, rte_errno, or -ret as well. The string is either strerror() or rte_strerror().