script/attr_count_read: load and correlate all data

script/attr_count_read: load and correlate all data

This changes script/attr_count_read to take the samba private directory
as an argument and load all the databases at once, printing them as
one big table. It isn't extremely clear what it all means, but it
*tries* to tell you.

With --plot, it will attempt to load matplotlib and plot the number of
requested attributes against the number returned, with colour
of each point indicating its relative frequency. It is a scatterplot
that wants to be a heatmap.

With --no-casefold, you can get an extra confusing table where,
for instance, something repeatedly asks for "attributeId" which is not
accounted for, while in a completely different row an unrequested
"attributeID" is found many times over.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Wed May  1 06:46:36 UTC 2019 on sn-devel-184