Fix 0012667: Moving issues between projects doesn't update the category

If an issue with category GUI is moved from Project A to Project B (where both have the category defined as non-global), then the issue will show the category name in the view page as "[Project A] GUI" even though the issue now belongs to project B. Also if the user edits the issue, the first category is selected from the list since "[Project A] GUI" is not a valid entry.

The proposed fix is as follows:

1. If the category is global, then leave as is.
2. If the category has a match by name in the target project, then switch to that.
3. If the category doesn't have a match by name in the target project, then move a configured default global category (by default "General").