REGTESTS: log: add a test for log-profile

REGTESTS: log: add a test for log-profile

Try to cover some common use-cases for "log-profile" feature. The tests
mainly focus on log-profile section declaration, and testing the behavior
of logformat / log-tag overriding capabilities.

For now, the use of log-profiles is somewhat limited because we lack
the ability to explicitly trigger the log building process at specific
steps during the stream handling. Indeed, for now we rely on
"option logasap" and proxy log-format string content "hacks" to force
the log emission at some specific steps, thus more tests should be added
over the time, when new mechanisms allowing the emission of logs at
expected processing steps will be added, or if new keywords are added to
the log-profile section.

This test requires versions >= 3.0-dev1