History page breaks with many packages

[jmdh]

We have a debomatic instance with around 5000 log files, and there are a couple of problems. Firstly, it gets very slow (to the extent that browser timeouts come into effect. If you allow the script to continue it does work but becomes a bit painful); secondly, it appears to start missing data, eg:

Jun 1 23:49:50 kale coffee[12327]: NO SOCKET: history:get_all_packages:readFile EMFILE: too many open files, open '/srv/debomatic/incoming/perl-5.24/pool/xmms2_0.8+dfsg-16/xmms2_0.8+dfsg-16.json'

I imagine that the latter issue could be fixed by someone who understand coffeescript/nodejs. I'm not sure what the right approach to fixing the former issue is.

Thanks for your work on debomatic-webui!