Merge branch '5612-apache-logs' into 'stable-3.1'

Issue #5612: Add CustomLog|ErrorLog to the Apache blacklist

Closes #5612

See merge request ispconfig/ispconfig3!1097

Author: Till Brehm

security/apache_directives.blacklist

@@ -1,3 +1,4 @@
 /^\s*(LoadModule|LoadFile|Include|IncludeOptional)(\s+|[\\\\])/mi
 /^\s*(SuexecUserGroup|suPHP_UserGroup|suPHP_PHPPath|suPHP_ConfigPath)(\s+|[\\\\])/mi
-/^\s*(FCGIWrapper|FastCgiExternalServer)(\s+|[\\\\])/mi
+/^\s*(FCGIWrapper|FastCgiExternalServer)(\s+|[\\\\])/mi
+/^\s*(CustomLog|ErrorLog)(\s+|[\\\\])/mi