Changelog:
Added OGC WFS and WMS services providing access to NEAMTHM18 and MPS04;
removed the outdated WMS and WMS EDSF13 dataset;
added fdsnws-events endpoints for ETHZ-SED, NOA, and Résif;
added two buttons for checking and unchecking layers provided via OGC services;
introduced datetime instead of the simple date for the event;
fixed a bug preventing the correct use of predefined symbology when using
fdsn-event in conjunction with the extended output based on QuakeML;
removed unwanted spaces from FDSN query parameters that may cause a Python
error;
splitted the monolithic JSON configuration file in multiple JSON files based on
the service type
