UCM13 — Add a method in the comp_trace policy to log messages with a default severity

The invocation of the standard technical policy for traces consists of a method
log that takes two parameters:

• the severity (trace, debug, warning, etc.)
• the log message (a wide character string)

It can be tedious to always have to specify the severity. There should be an
additional log method with a default severity.

Do not change the comp_trace policy

No commonly used logging API (e.g. log4cpp) supports a default severity level. Therefore, such a mechanism does not correspond to current pratice, and may be difficult to understand.

Platform providers that really want to deal with a default severity loggin level can define their own, non standard, technical policy.