Review earthquake scenarios for Italy, Cyprus and Netherlands

[martinacaruso]

This PR reviews and integrates impact data for earthquakes scenarios in Italy, Cyprus and Netherlands.

Minor changes were included:

• adding some impact data at the national levels
• updating the earthquake information csvs and READMEs with the preferred ranges of impact data
• reviewing the style of the references in the READMEs of the Impact folders
• converting some levels of damage from different sources into the damage states suggested by EMS-9
• reviewing the moment magnitude of some events, updating the READMEs to be consistent

While reviewing Italian events, a few inconsistencies were found, which are summarised in the issue #52.