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

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()`.