Add unique HTTP request id to logs

To make identifying logs of any kind which are related to a given HTTP request, a unique identifier should be generated and added to the logs.

In sonar.log, it should be added in the "field" after "web", so this:

2016.11.02 18:23:01 TRACE web[][sql] time=0ms | sql=select id, data     from notifications     order by id asc     limit ? | params=1

will become this:

2016.11.02 18:23:01 TRACE web[XXXXXXXXXX][sql] time=0ms | sql=select id, data     from notifications     order by id asc     limit ? | params=1

It will also be possible to display this identifier in "access.log" by adding %reqAttribute{ID} to the pattern.

Obviously, the generation of the unique identifier should be super fast to not create an overhead on each and every HTTP request.