(QENG-846) Centralized dated log path generation, and added options for specific log paths

Before, the latest link was hard to use since it jumped around, and you couldn't really get at
the timestamped log path itself because it was hidden in the log_path function.  This work
separates out the timestamped path generation into a static method so that it can be used
anywhere, and adds the current usages of it to the global options, so that they can be used
for other purposes, such as the use case for this issue: copying other files to this location
Merge pull request #529 from kevpl/qeng846_logpath

(QENG-846) Centralized dated log path generation, and added options for ...