[TASK] Replace URLs of bugs.typo3.org with forge.typo3.org

The old issue tracker on http://bugs.typo3.org will be shut down
by the end of 2013.

Therefore replace *all* occurrences of such URLs with the new
location on http://forge.typo3.org.

Change-Id: Ia44742efeab22837dd5be7076f21eb286aaf5a82
Resolves: #54020
Releases: 6.2
Reviewed-on: https://review.typo3.org/25716
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters