Bug 11926: Render community koha statistic usages

Bug 11926: Render community koha statistic usages

Goals:
- Collecting Koha usage statistics
- Rendering stats on a community website
- Having a big bicture of how koha is used

3 parts in the project:
- this patch in koha
- hea-ws which collects data
- hea-app which renders data

Installation:
1/ Fill systempreferences:
UsageStatsLastUpdateTime UsageStatsID UsageStatsShare UsageStatsLibraryName
2/ Setup a cron in your crontab (ex: at 3:00 every first of the month):
0 3 1 * * export KOHA_CONF=/home/koha/etc/koha-conf.xml; export PERL5LIB=/home/koha/src; perl /home/koha/src/C4/UsageStats.pm

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>