Provide an option to disable cleaning of group names, or change the cleaning regex

TRUSTAUTH-29 introduced the automated cleaning of group names, however this may not work out well with existing users of the application, that have already used some group mappings (with non-recommended characters) to have groups provisioned. These groups may be quite difficult to rename because rights could be associated to them all through the wiki.

One solution would be to provide two configuration options :

• One allowing to disable the cleaning of groups altogether. We could then enable the cleaning by default, and add a note in the release notes that users upgrading should review their group mappings and consider introducing this option.
• One allowing to modify the regular expression used to clean groups : administrators may want to remove only some special characters, or remove other characters we don't remove by default.