Improve admin console log viewer

The Openfire admin console allows the user to view log files that are generated by Openfire. This page needs to be improved.

• Openfire should no longer log different log levels to different files (error.log, warn.log, etc). This is confusing, as these files hide context for the problem. Openfire already creates an 'all.log' that combines everything - we should use only that.

• The tabs on the page (to switch from all to error to warn, etc) should be removed.

• The text area size should dynamically resize to the size of the screen

• Filter options should be added, to filter the logs based on warning level, logger name, timestamp, and so on.