Improve the format of the rotation template by date

Is it possible to add the ability to rotate by date so that you can specify not only the pattern, but also the path using the pattern.
For example: filePattern="logs/arch/{yy-MM-dd}/add/update.log"

Start by tracing how filePattern is handled in streamroller's existing date/time rollover path. Define how a date token in a directory path should be expanded, using logs/arch/{yy-MM-dd}/add/update.log as the target behavior. Done means rotation creates and writes to the date-based path while preserving existing pattern behavior.

Written by the indexing model from the issue text.