[GDLT-120]: Improved Network trace. Rewrite to POSIX queue.

[GDLT-120]: Improved Network trace. Rewrite to POSIX queue.

This is a squash of multiple commits. The original commit messages follow.

[GDLT-120]: Segmented network trace: Correct error condition checks.

[GDLT-120]: Add documentation for extended network trace

[GDLT-120]: Add dlt_queue. Linked list based dynamic queue.

[GDLT-120]: Recode to using queue for segmented messages

[GDLT-120]: Improved thread start handling. Add error handling.
Remove libm from linkage.

[GDLT-120]: Avoid sending an extraneous empty segment, when size is aligned

[GDLT-120]: More expansive return values from dlt_user_log_send_log

[GDLT-120]: Change default behaviour of dlt_user_trace_network to truncated, instead of discard.

[GDLT-120]: Convert to POSIX queue.

Signed-off-by: Alexander Wenzel <Alexander.AW.Wenzel@bmw.de>