perf: add async log writer

[kolesnikovae]

The PR adds asynchronous log writer.

Recently implemented buffered logged (#3947) does not address the issue with blocking log writes:

The implementation we use flushes the buffer synchronously, blocking all callers. To address the problem, we should use asynchronous writer. The implementation in the PR implements a queue that is processed in background:

• when the queue is full, new writes are discarded.
• by default, the queue is large enough to store 20K messages or 5MB.
• errors are ignored since we can't do anything if stderr is not available (which is the cause of errors).