daemon/worker and daemon/session cleanup

Depends on !1054 (merged) (and rebased on top of it).

changed milestone to %5.2.0

added refactoring label

assigned to @sbalazik

@sbalazik Please review this. Thanks!

This looks good to be as well, thanks for the continued work in cleaning up session and worker even if it often feels like pushing a Sisyphus' rock.

approved this merge request

added 56 commits

• 8b014778...0a040a36 - 52 commits from branch master
• 82e74cf6 - daemon/io: don't notify worker on udp_recv() errors
• 268dc8aa - daemon/worker: use proper name for packet in worker_submit()
• 42ee46dc - daemon/worker: simplify err handling in worker_submit()
• 12488f54 - daemon/session: use common naming convention in the entire file

Compare with previous version

mentioned in commit bb808ad1

merged