UTF-8 characters in property files do not render properly and must be escaped

During verification of GOGREEN-1221 found an issue with some of the translations using UTF-8 code in property files. This is not allowed and unicode must be escaped.
I did a quick check [1] on non-ascii property values, this also is a problem in the cms and plugins.

Verified in the UI. One of the found properties found:

cms/perspectives/src/main/java/org/hippoecm/frontend/plugins/cms/dashboard/current/CurrentActivityPlugin_it.properties:3:login=<span class="light">

si è connesso</span>

indeed renders incorrectly on the CMS dashboard as Dieci minuti fa, admin si è disconesso

All .properties files intended for the Java properties class must have escaped unicode characters.

[1] grep -r --include=*.properties --color='auto' -P -n "[\x80-\xFF]" *