Update default configuration

* Update MathJax URL to use version 2.7.5
* Piwik was renamed to Matomo

src/main/resources/arsnova.properties.example

@@ -207,7 +207,7 @@ connector.password=test
 # Enable MathJax to allow the use of Math formulas written in TeX syntax in
 # text fields.
 features.mathjax.enabled=true
-features.mathjax.src=//cdn.mathjax.org/mathjax/2.4-latest/MathJax.js
+features.mathjax.src=//cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js
 
 # The following features are considered experimental because they have not been
 # tested in a production environment over a longer time frame and/or their
@@ -322,8 +322,8 @@ pp.session-levels.en = General Education,\
 # Tracking
 ################################################################################
 # It is possible to use an external tracking software with ARSnova. Currently
-# Piwik is the only supported tracking provider.
+# Matomo is the only supported tracking provider.
 #
-tracking.provider=piwik
+tracking.provider=matomo
 tracking.tracker-url=
 tracking.site-id=

src/test/resources/arsnova.properties.example

@@ -207,7 +207,7 @@ connector.password=test
 # Enable MathJax to allow the use of Math formulas written in TeX syntax in
 # text fields.
 features.mathjax.enabled=true
-features.mathjax.src=//cdn.mathjax.org/mathjax/2.4-latest/MathJax.js
+features.mathjax.src=//cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/MathJax.js
 
 # The following features are considered experimental because they have not been
 # tested in a production environment over a longer time frame and/or their
@@ -322,8 +322,8 @@ pp.session-levels.en = General Education,\
 # Tracking
 ################################################################################
 # It is possible to use an external tracking software with ARSnova. Currently
-# Piwik is the only supported tracking provider.
+# Matomo is the only supported tracking provider.
 #
-tracking.provider=piwik
+tracking.provider=matomo
 tracking.tracker-url=
 tracking.site-id=