This takes care of timestamp columns, modifies queries in a way not
depending on db functions, filters are passed through to subqueries
for better performance.
It doesn't make much sense to sort history by "hostname" hardcoded to
service-only host columns. Default is now timestamp DESC, internally
this is mapped to raw_timestamp.
the Monitoring/View code was completly dropped in favor of
the DataView implementations, as new Backends otherwise
would require to implement two seperate query logics
refs #3801
Eric Lippmann
Johannes Meyer
Thomas Gelf
Jannis Moßhammer