Add "hide prefixed projectname from issuesubject on issuelist" setting
This issue is extracted from #3100 and it's relatives. The patch adds a new system-wide, issue-tracking setting (
hide_prefixed_projectname_from_issuesubject_on_issuelist) which provides the administrator an option to hide the subproject name (which is prefixed in front of the issue descriptions on mainproject issue lists) completely.
Such a setting can be useful if the site is configured to display the
project-column be default.
The default setting is equal to as it is currently(the projectnames are shown prefixed to the descriptions).