Enhance scraper log archiving
Enhance scraper log archiving

This commit implements putting the log archive files in the
logarchive subdirectory to prevent clutter.

It also implements deleting old log files per the following
configuration file (or command line) parameters:

deleteoldlogarchives=0|1 (default true)
logarchiveretainnumfiles=x (default 14)

deleteoldlogarchives defaults to true, which then means that
every time the log archiver is triggered (typically at midnight UTC)
it will archive the current scraper log file into the logarchive
directory, and then apply the rule to retain the x most recent files,
where x is specified by logarchiveretainnumfiles.

An immediate archive (and directory cleanup) can be triggered by issuing
the rpc command archivescraperlog.

If deletelogarchives is set to false, then the scraper.log files are
archived into the logarchive directory, but never deleted.

Git-Jiro/Gridcoin-Research,gridcoin/Gridcoin-Research,gridcoin/Gridcoin-Research,Git-Jiro/Gridcoin-Research,theMarix/Gridcoin-Research,Git-Jiro/Gridcoin-Research,gridcoin/Gridcoin-Research,gridcoin/Gridcoin-Research,Git-Jiro/Gridcoin-Research,theMarix/Gridcoin-Research,theMarix/Gridcoin-Research,caraka/gridcoinresearch,gridcoin/Gridcoin-Research,caraka/gridcoinresearch,theMarix/Gridcoin-Research,caraka/gridcoinresearch,theMarix/Gridcoin-Research,caraka/gridcoinresearch,gridcoin/Gridcoin-Research,theMarix/Gridcoin-Research,Git-Jiro/Gridcoin-Research,caraka/gridcoinresearch,caraka/gridcoinresearch