Week Year instead of Calendar Year in documentation and config file

[akasparas]

SimpleDateFormat and FastDateFormat libraries format YYYY and yyyy diferently. 
yyyy is 'Calendar Year' and should be used in most places in documentation and examples. 
YYYY is 'Week Year' and should be used only with week number, like "YYYY-'W'ww".

Year 2026 started on Thursday, so week 2026-W01 started on 2025-12-29 and on 
that day $date.YYYY-MM-dd$ was instantiated as 2026-12-29. Finding directories 
with such dates confused me a lot. And this would not happen, if I would used 
lowercase yyyy in configuration.

So, what should be fixed?
- Documentation, paragraph 8. Dynamic variables. $date.YYYY$ should be 
  replaced with $date.yyyy$. It would be good idea to discourage use of 
  $date.YYYY$ with explanation why. And also mention that it is not necessary 
  to use several date variables for year, month, day, etc--it's possible to write 
  complex date format in one variable.
- Server/src/config/config.xml /config/properties/@pollerConfigBase.errordir -- 
  change $date.YYYY$--$date.MM$-$date.dd$ to $date.yyyy-MM-dd$

[uhurusurfa]

Thaks for the report on this issue.

I will update all the documentation and correct the default config in the next release.