Remaining error logging todos

This issue is the follow up to TRANSLATE-613 and holds all open todos from there.

• refactor all remaining old exceptions and old log usages
  → Until this is done, the legacy code remains
• Error Messages should be creatable via the frontend (only with valid session). This enables us to log from the GUI into the DB. This could be necessary in some cases, since therootcause is only usefol for log exceptions. But for debugging it may be necessary to log down other content from the GUI. (For example URLs which produce an Ajax timeout).
• Der Http Logger ein ausschaltbar, perspektivisch alle aktuellen Debug Statements durch den logger ersetzen (goes hand in hand with TRANSLATE-354)
• More descriptive exceptions: Example with missing rights (user hierarchy etc) it is possible to get a ZfExtended_Models_Entity_NoAccessException on opening a task. There is no info about why there is no access.
• editor_Plugins_MatchAnalysis_Analysis errors in language resource communications must be logged too (and communicated to the user)
• The amount of warnings / infos / errors of a task should be visible in the task overview (idea: like message count on app icon in mobile phones). If this is done, the warn mail to PM in the task log writer can be removed.