Resolve "add rates from ugt and ugmt"

Closes #52 (closed)

The current branch includes the following features and changes:

• Rates are now polled from databases for global algo and muon rates, calo rates do not yet have a query and only an empty array is sent to the client. The rates poller listens for the 'new data' event of the general db poller, but only starts polling if the lumi section changes. The polling to the rates database is repeated every 5 seconds until an array with rates is obtained or until the next lumi section arrives. All three rates pollers send individual events ('new global rate', 'new muon rates', 'new calo rates')
• The rates are displayed in a panel, where the global rates are currently displayed in the order that they are sent from, from the api, which is ordered by rates from high to low. For the muon rates the rates are split into subpanels, one for each muon subsystem. The subpanels are ordered geographically from EMTF+ to EMTF-. Sorter rates and the final input rate are displayed at the top.
• It is possible to set thresholds on the individual rates by specifying them in node modules. The directory from which these modules are loaded can be set in settings/rates/ (any filename will work, as long as there is only one). Changes to any threshold module file or the location settings file are automatically detected and the thresholds are updated accordingly.
• To make the latter part work more easily, the automatic watching of modules, which was previously employed by the suggestions has been generalized and applied in the same manner to the rates thresholds.

Open points:

• Currently the rates thresholds only are only applied for the general threshold, but not for individual thresholds. (With 48a708dc the basic functionality is in place, but not used anywhere at the moment)
• See #58 (closed) for some already present additional feature requests