Improve HLT jet monitoring, and use JetRecAlg more widely

Various improvements:

• Renamed some monitored variables for clarity
• Tweaked histogram ranges
• Replaces outdated JetAlgorithm+JetRecTool with new JetRecAlg (some additional modifiers were needed, and the odd config change)

Attn @jbossios, @valentem -- do we want to discuss in more detail what we want to have monitored? Among other things I note that we don't have any monitoring of the jet mass, which might be relevant for some chains. There was also discussion of pileup-dependent histograms.