Change: move filtered counts into print_report_xml_start context

[mattmundell]

What

Move the f_host_* variables from the body of the print_report_xml_start into the ctx struct.

This is a very simple first step,, to keep the patch easy to understand. It only moves the variables.

Note that the NULL inits are redundant but I've kept them in for now, to minimize changes.

Why

I'm reducing the size of the very large print_report_xml_start, to make it easier to maintain.

References

Follows /pull/2693.

Breakdown of /pull/2712.

Testing

I ran GET_REPORTS on branch and main, and compared the output.

o m m '<get_reports report_id="82f3531c-43cd-4453-8300-990dc423d96b" filter="apache levels=hm" details="1"/>' > /tmp/r-pr
o m m '<get_reports report_id="82f3531c-43cd-4453-8300-990dc423d96b" filter="apache levels=hm" details="1"/>' > /tmp/r-main
o m m '<get_reports details="1"/>' > /tmp/r2-pr
o m m '<get_reports details="1"/>' > /tmp/r2-main
diff -u /tmp/r-pr /tmp/r-main
diff -u /tmp/r2-pr /tmp/r2-main